PC231/PC241 EIGHT CHANNEL SERIAL COMMUNICATIONS BOARD WITH ISOLATION OPTION

Transcription

1 PC231/PC241 EIGHT CHANNEL SERIAL COMMUNICATIONS BOARD WITH ISOLATION OPTION This Instruction Manual is supplied with the PC231 and PC241 Series of Serial Data Communications Board to provide the user with sufficient information to utilise the product in a proper and efficient manner. The information contained has been reviewed and is believed to be accurate and reliable, however Amplicon Liveline Limited accepts no responsibility for any problems caused by errors or omissions. Specifications and instructions are subject to change without notice. PC231 and PC241 Instruction Manual Part Nº Issue A3 Amplicon Liveline Limited Prepared by C.A. Kenny Approved for issue by A.S. Gorbold, Operations Director PC231/PC241 Series

2 DECLARATION OF CONFORMITY AMPLICON LIVELINE LIMITED CENTENARY INDUSTRIAL ESTATE HOLLINGDEAN ROAD BRIGHTON BN2 4AW UK We declare that the product(s) described in this Instruction Manual are manufactured by Amplicon Liveline Limited and perform in conformity with the following standards or standardisation documents: Electro Magnetic Compatibility (EMC): EMC Directive 89/336/EEC LVD Directive 73/23/EEC CE Directive 93/68/EEC Jim Hicks, I. Eng, MIEIE Managing Director Amplicon Liveline Limited PC231/PC241 Series

3 PC231(i) and PC241(i) Eight Channel Serial Communications Boards with Optional Isolation LIST OF CONTENTS PARA SUBJECT PAGE 1 INTRODUCTION The Amplicon 200 Series The Products Described in this Manual Features of the PC231/PC241 Series of Data Communications Boards General Description What the Package Contains The Amplicon Warranty Covering the PC231/PC241 Series of Boards Contacting Amplicon Liveline Limited for Technical Support or Service Technical Support Repairs 4 2 GETTING STARTED General Information Notes for Users of Existing Amplicon Serial Communications Boards Installing the Board Host Computer Requirements Backing up the Software Diskette Configuration Switch and Jumper Settings Base Address Selection Factory Settings for the Channel Base Addresses User Configured Base Addresses Simple Set-up of Base Addresses for up to Eight Boards Channels 1 and/or 2 Inhibit PC I/O Map Interrupt Level Selection Factory Settings for the IRQ Levels User Configured IRQ Levels Interrupt Group Selection Individual Channel Interrupt Level Selection Selection of Shared or Non-Shared Operation IRQ Assignments RS-422/485 Full Duplex / Half Duplex Operation Selection of Full/Half Duplex Selection of Local Echo On/Off in Half Duplex Operation Transmission Line Termination Termination Resistors for RS-422/485 Receivers Switch and Jumper Factory Settings Summary Software Installation Installation Testing 20 3 MAKING THE CONNECTIONS Direct Connections via the 78 Way I/O Socket External Connections via Optional Panels RS way Port RS way Port RS-422/485 9 way Port Connector Wiring for RS-422/485 Full/Half Duplex The Ground Connections Ground Connections for Non-isolated Boards Ground Connections for Isolated Boards PC Back-plane Bus Connections 28 PC231/PC241 Series

4 4 USING THE SERIAL COMMUNICATIONS BOARDS Why Isolate? Application Notes Applicable Standards RS-232 Application Notes Electrical Levels Data Rates and Cable lengths RS-232 Cable Adaptors RS / 25 way Adaptors RS-232 DTE to DTE Adaptors Connection to a Modem or Other DCE RS-422/485 Application Notes RS-422/485 Parameters RS-422/485 Signalling Sense RS-422/485 Multi-drop Applications RS-422/485 Bus Termination Cabling of RS-422/485 Bus Testing and Troubleshooting Testing with the Application Software Testing Using the Supplied Software The Loop Back Connections Loading and Using TEST_COM Loop-back Testing Using A Terminal Emulator 41 5 STRUCTURE AND ASSIGNMENTS OF THE REGISTERS Register Assignments Register Groups The Register Details Receiver Buffer Register (RBR) Transmitter Holding Register (THR) Least and Most Significant Divisor Latch Registers (DLL and DLM) Interrupt Enable Register (IER) FIFO Control Register (FCR) Interrupt Identification Register (IIR) Line Control Register (LCR) Modem Control Register (MCR) Line Status Register (LSR) Modem Status Register (MSR) Scratchpad Register (MSR) 65 6 PROGRAMMING COMBIOS Serial Communication Basic Input/Output System General Description Features COMBIOS for Windows General Description Features of COMBIOS for Windows Typical Applications Functions Provided by COMBIOS for Windows The COMBIOS for Windows Package User Programming Programming the UART FIFO Interrupt Mode Operation FIFO Polled Mode Operation Interrupt Operations Non-shared Interrupts Shared Interrupts Shared Interrupts Programming Hints Half Duplex Transmission Turnaround 73 PC231/PC241 Series

5 LIST OF APPENDICES PARA SUBJECT APPENDIX A App A1 App A1.1 App A1.2 App A1.3 App A1.4 App A1.5 App A1.6 App A1.7 App A1.8 App A2 App A3 App A3.1 App A3.2 App A3.3 App A4 App A5 App A5.1 App A5.2 APPENDIX B APPENDIX C App C.1 App C.2 App C.3 App C.4 App C.5 App C.6 App C.7 App C.8 App C.9 TECHNICAL SPECIFICATIONS Hardware Specification Function Board I/O Connector RS-232 Port PC231 and PC231i RS-422/485 Port PC241 and PC241i UARTS Channel Inhibit Interrupts PC Interface Software Environmental Conditions Environment Specific conditions Electromagnetic Compatibility Order Codes Optional Accessories Hardware Options Software Options GLOSSARY OF TERMS CIRCUITS AND LAYOUTS Circuit Functions PC231, PC231i, PC241 and PC241i - All Versions Circuit Functions PC231 RS-232 Drivers and Receivers Circuit Functions PC241 RS-422/485 Drivers and Receivers Circuit Functions PC231i RS-232 Isolated Drivers and Receivers Circuit Functions PC241i RS-422/485 Isolated Drivers and Receivers PC231 PC Board Layout PC241 PC Board Layout PC231i PC Board Layout PC241i PC Board Layout PC231/PC241 Series

6 LIST OF FIGURES FIGURE TITLE PAGE FIG 2.1 STANDARD BASE ADDRESSES FOR UP TO EIGHT BOARDS 8 FIG 2.2 A CHANNEL BASE ADDRESS TABLE 160-3F8 9 FIG 2.2 B CHANNEL BASE ADDRESS TABLE 560-7F8 10 FIG 2.3 ADDRESS SWITCH SETTING TABLE 11 FIG 2.4 PC I/O MAP ASSIGNMENTS 12 FIG 2.5 SWITCH SELECTION OF INTERRUPT GROUP 14 FIG 2.6 INDIVIDUAL INTERRUPT SWITCH POSITIONS 14 FIG 2.7 INDIVIDUAL INTERRUPT SWITCH SETTINGS 15 FIG 2.8 INTERRUPT SHARING SELECTION 16 FIG 2.9 INTERRUPT LEVEL ASSIGNMENTS 16 FIG 2.10 JUMPER SETTING FOR FULL/HALF DUPLEX 17 FIG 2.11 JUMPER SETTING FOR ECHO IN HALF DUPLEX MODE 18 FIG 2.12 FACTORY SWITCH AND JUMPER SETTING SUMMARY 19 FIG WAY I/O CONNECTOR PIN DESIGNATIONS 21 FIG 3.2 ACCESSORY I/O CABLE/PANEL ASSEMBLY 22 FIG 3.3 EXTERNAL I/O PANEL LAYOUTS 23 FIG 3.4 RS WAY PORT PIN DESIGNATIONS 23 FIG 3.5 RS WAY PORT PIN DESIGNATIONS 24 FIG 3.6 RS-422/485 PORT PIN DESIGNATIONS 24 FIG 3.7A CONNECTIONS FOR FULL AND HALF DUPLEX OPERATION (9 PIN) 25 FIG 3.7B CONNECTIONS FOR FULL AND HALF DUPLEX OPERATION (78 PIN) 25 FIG PIN ISOLATED RS-232 CONNECTIONS TO ANOTHER DTE DEVICE 27 FIG 3.9 PC BACKPLANE ISA BUS CONNECTIONS 28 FIG 4.1 ELIMINATION OF INTERFERING SIGNALS BY ISOLATION 30 FIG 4.2 DTE ADAPTOR - 9 WAY TO 25 WAY 33 FIG 4.3 DTE TO DTE NULL MODEM WITH CROSS-CONNECTED CONTROL LINES 33 FIG 4.4 DTE TO DTE NULL MODEM WITH LOOPED-BACK CONTROL LINES 34 FIG 4.5 COMMUNICATIONS STANDARDS SUMMARY 35 FIG 4.6 RS-422 CONNECTED IN BROADCAST MODE 36 FIG 4.7 RS-485 CONNECTED IN MULTI-DROP, HALF DUPLEX MODE 36 FIG 4.8 RS AND 9 WAY LOOP-BACK TEST CONNECTIONS 39 FIG 4.9 RS-422/485 LOOP-BACK TEST CONNECTIONS 40 FIG 5.1 REGISTER ASSIGNMENTS 42 FIG 5.2 THE REGISTERS OF EACH UART 43 FIG 5.3 BLOCK DIAGRAM OF SINGLE CHANNEL UART SHOWING THE REGISTERS 44 FIGURES IN APPENDICES FIGURE TITLE FIG C.1 PC231(i)/241(i) CIRCUIT SCHEMATIC PC INTERFACE FIG C.2 PC231(i)/241(i) CIRCUIT SCHEMATIC INTERRUPTS AND UARTS FIG C.3 PC231 CIRCUIT SCHEMATIC EIGHT CHANNEL RS-232 I/O FIG C.4 PC241 CIRCUIT SCHEMATIC EIGHT CHANNEL RS-422/485 I/O FIG C.5 PC231i CIRCUIT SCHEMATIC OPTO-ISOLATORS CHANS 1-4 FIG C.6 PC231i CIRCUIT SCHEMATIC OPTO-ISOLATORS CHANS 5-8 FIG C.7 PC231i CIRCUIT SCHEMATIC EIGHT CHANNEL RS-232 I/O FIG C.8 PC241i CIRCUIT SCHEMATIC OPTO-ISOLATORS CHANS 1-4 FIG C.9 PC241i CIRCUIT SCHEMATIC OPTO-ISOLATORS CHANS 5-8 FIG C.10 PC241i CIRCUIT SCHEMATIC EIGHT CHANNEL RS-422/485 I/O FIG C.11 PC231 LAYOUT DIAGRAM FIG C.12 PC241 LAYOUT DIAGRAM FIG C.13 PC231i LAYOUT DIAGRAM FIG C.14 PC241i LAYOUT DIAGRAM PC231/PC241 Series

7 PC231(i) and PC241(i) Eight Channel Serial Communications Boards with Isolation Option 1 INTRODUCTION 1.1 The Amplicon 200 Series The Amplicon 200 Series of Personal Computer based data acquisition, control and communication products provides very high performance, affordable hardware and user sympathetic software. The 200 Series is designed for users requiring fast or complex data input/output to the host computer and comprises a range of boards and software to handle most analog and digital signal types. When a large scale system is required, multiple boards can be added from the 200 Series without conflict. In many cases the capacity of the PC mounted hardware can be extended by external expansion and termination panels, which together with the applicable cables, provide a convenient to use system with low cost per channel and maintained high performance. 1.2 The Products Described in this Manual The PC231 and PC241 Series of communications products includes four variants of eight channel boards with supporting hardware, software and accessories. The boards share common circuits and features, and are generically cited in this manual as the PC231/PC241 Series. Where a specific board type, or pair, is referenced, nomenclature as in the following examples is used:- PC231/PC241 Series PC231 PC241i PC231(i) Refers to all boards in the series Refers to the PC231 only (Eight channel RS-232) Refers to the PC241i only (Eight Channel RS-422/485 with isolation) Refers to the PC231 with or without isolation 1.3 Features of the PC231/PC241 Series of Data Communications Boards Each of the PC231/PC241 Series of boards is designed to meet stringent performance requirements and ease of use while maintaining compatibility with earlier boards. Marked Multi-port isolated serial communications Eight separate, independent serial ports provide up to 64 channels in a single PC Choice of industry standard connectors on external panel with integral cable Flexible addressing Multiple, selectable IRQ levels Shared interrupt capability Multiple modes. RS-232, 25 and 9 way ports, RS-422, RS-485 Full Duplex, Half Duplex, Multi-drop applications FIFO mode provides input and output data buffers Data rates up to kbd Full specification signal levels Implementation of all RS-232 primary control lines Low power consumption Test software included, optional software packages according to requirements PC231/PC241 Series Page 1

8 1.4 General Description The PC231/PC241 Series of plug-in boards provides a flexible range of serial communications interfaces for the IBM PC and compatible computers. Four models are available in the range, two of which provide multi-port isolation of the data and control lines. The PC231i and PC241i boards with isolated input/output circuits will be used in serial communications systems where high integrity data transmission and reception are required in an electrically severe environment. Each board is full length and supports eight independent serial ports designed to meet a combination of the following standards: RS-232 full or half duplex serial port furnished with a 25 pin D-type male connector wired as DTE to international standards. The port is provided with two data and a full complement of six control I/O lines. RS-232 full or half duplex serial port furnished with a 9 pin D-type male connector conforming to the EIA/TIA (RS)-574 standard and IBM practice. The port is fully configured with two data and a full complement of six control I/O lines. RS485 full duplex, half duplex, multi-drop operation or RS422 full duplex with or without RTS-CTS control lines. Depending on the application, RS485 or RS422 operation is selected by making the appropriate connections. Each RS422/485 port can be furnished with a 9 pin D-type male connector. Serial input/output facilities of the Series comprise: PC231 PC241 PC231i PC241i Provides eight independent RS-232 ports on a 78 way I/O connector. An optional, external connector panel provides eight independent 9 or 25 way, industry standard I/O connectors Provides eight independent RS-422/485 ports on a 78 way I/O connector. An optional, external connector panel provides eight independent 9 way, I/O connectors Provides eight independently isolated RS-232 ports on a 78 way I/O connector. An optional, external connector panel provides eight independent 9 or 25 way, industry standard I/O connectors Provides eight independently isolated RS-422/485 ports on a 78 way I/O connector. An optional, external connector panel provides eight independent 9 way, I/O connectors Communications parameters of all eight ports of all versions are fully programmable for compatibility with other devices connected to the interface and to allow set up by the communications program. A diskette is provided with a program to facilitate testing of the major features of the board when installed in the host PC. Separate DOS or Windows based software drivers are available from Amplicon Liveline Ltd to add interrupt driven, multi-port serial communications to programs written in most languages. Demonstration versions of these COMBIOS software packages are included on the distribution diskette. Page 2 PC231/PC241 Series

9 The PC231i and PC241i are designed to isolate the serial communication from the computer power. The design is such that it will sustain common mode voltages up to 75vdc, which is outside of the Low Voltage Directive (73/23/EEC). However in fault conditions they are protected to sustain common mode voltages up to peaks of 250vdc 1.5 What the Package Contains! CAUTION Some of the components on the board are susceptible to electrostatic discharge, and proper handling precautions should be observed. As a minimum, an earthed wrist strap must be worn when handling the PC231/PC241 Series board outside its protective bag. Full static handling procedures are defined in British Standards Publication BSEN100015/BSEN :1992. When removed from the bag, inspect the board for any obvious signs of damage and notify Amplicon if such damage is apparent. Do not plug a damaged board into the host computer. Keep the protective bag for possible future use in transporting the board. The package as delivered from Amplicon Liveline Ltd contains:- 1. The plug-in board as ordered, in a protective bag. The model will be one of the following, and is identified by the type number printed on the board. PC231 PC241 PC231i PC241i Eight channel RS-232 Serial Communications Controller Eight channel RS-422/485 Serial Communications Controller Eight channel RS-232 Serial Communications Controller with I/O signal isolation Eight channel RS-422/485 Serial Communications Controller with I/O signal isolation 2. This Instruction Manual. Part Nº The included 200 Series Serial Communications distribution software on a 3 1 /2 inch high density diskette. Part Nº Any additional accessories (I/O connector panel and cable, mating connectors, software etc.) may be packed separately. PC231/PC241 Series Page 3

10 1.6 The Amplicon Warranty Covering the PC231/PC241 Series of Boards This product is covered by the warranty as detailed in the Terms and Conditions stated in the current domestic or international Amplicon Liveline catalogue. 1.7 Contacting Amplicon Liveline Limited for Technical Support or Service The PC231/PC241 Series boards are designed and manufactured by Amplicon Liveline Ltd and maintenance is available throughout the supported life of the product TECHNICAL SUPPORT Should the board appear defective, please check the information in this manual and any 'Help' or 'READ.ME' files appropriate to the program in use to ensure that the product is being correctly applied. If an application problem persists, please request Technical Support on one of the following numbers: Telephone: UK International Fax: UK International Internet Repairs If the board requires repair then please return the goods enclosing a repair order detailing the nature of the fault. If the board is covered by the Amplicon warranty, there will be no repair charge. For traceability when processing returned goods, a Returned Materials Authorisation (RMA) procedure is in operation. Before returning the goods, please request an individual RMA number by contacting Amplicon Customer Services by telephone or fax on the above numbers. Please mark the RMA number on the outside of the packaging to ensure that the package is accepted by the Goods Inwards Department. Give the reason for the return and, if the goods are still under warranty, the original invoice number and date. Repair turnaround time is normally five working days but the Service Engineers will always try to co-operate if there is a particular problem of time pressure. Address repairs to: Customer Services Department AMPLICON LIVELINE LIMITED Centenary Industrial Estate Brighton, East Sussex BN2 4AW England Page 4 PC231/PC241 Series

11 2 GETTING STARTED 2.1 General Information Each board from the PC231/PC241 Series is factory configured so that it may be installed in a suitable host PC and allow execution of a normal serial communications program, the supplied loop-back test program or an applications program using COMBIOS drivers. 2.2 Notes for Users of Existing Amplicon Serial Communications Boards To use the PC231(i) board in RS-232 programs or systems prepared for the earlier PC31AT, check the following point: The earlier PC31AT eight port board will only share interrupts with another PC31AT. The PC231(i) board uses ISA shared interrupt structure and can operate with any compliant adaptor. To use the PC241(i) board in RS-485 half-duplex programs or systems prepared for the earlier PC47AT, PC48AT or PC49AT, check the following points: Transmission turn-around in half duplex operation is now controlled by RTS (Bit 1 of the Modem Control Register) instead of /OUT1 (Previously bit 2 of the Modem Control Register). This transmission turnaround feature is not normally used in standard communications programs, but may have been implemented in bespoke software. The external two-wire connection for half duplex operation needs to be linked to both Rx and Tx pin pairs of the 9 way connector. (See figure 3.7) For conformance with the latest RS-422/485 standard specifications, the nomenclature of the data lines is amended. The RS-422/485 levels and polarities remain unchanged and the actual external data bus wiring needs no changes. 2.3 Installing the Board Depending on other adaptors that may be installed in the host PC or on the requirements of the user, changes to the hardware set-up of the PC231/PC241 Series board may be necessary before installation. The necessary configuration settings are described in this chapter. ENSURE THAT THE POWER TO THE COMPUTER IS SWITCHED OFF BEFORE INSTALLING OR REMOVING ANY EXPANSION BOARD. OBSERVE HANDLING PRECAUTIONS NOTED IN SECTION 1.5. REPAIR OF DAMAGE CAUSED BY MIS- HANDLING IS NOT COVERED UNDER THE AMPLICON WARRANTY. DO NOT MAKE ANY MODIFICATIONS OTHER THAN SWITCH OR JUMPER CHANGES TO A BOARD THAT IS ON EVALUATION Please refer to the manufacturer's hardware manual supplied with the computer for instructions on how to remove the cover and install devices into an input/output slot. The board may be installed in any available position in the machine provided that there is no restriction specified for that location by the computer manufacturer. To maintain safety, physical integrity and proper EMC compliance, ensure that after plugging the board in position:- 1. The board is held in position by the single fixing screw on the 'L' bracket. PC231/PC241 Series Page 5

12 2. The covers of the host PC are properly located and all fixing screws put back in position. The PC231/PC241 Series board is factory configured ready to run with communications programs that normally support COM1 to COM 8 devices and shared interrupts. If there are no other devices installed in the computer that are likely to cause conflicts, then for initial familiarisation purposes the board will need no configuration switch changes. Refer to the relevant paragraphs in sections 2.7 through 2.11 if a change of base address, interrupt configuration or RS-422/485 jumper setting needs to be made before installing the PC231/PC241 Series board in the computer. 2.4 Host Computer Requirements When installing one or more PC231/PC241 Series Data Communications Boards, ensure that the host computer has sufficient capacity. Take into account other boards or adapters that may be installed in the computer when assessing physical space, address space in the I/O map, interrupt levels and the power requirements. This eight channel serial communications board is suitable for use in any PC compatible computer that can provide a single ISA standard 16 bit I/O slot, with sufficient space for a full length card. If the only slot available is an 8 bit type, then the higher interrupt levels will not be usable. Shared interrupts are not supported by XT versions and the usability of the board would be limited. Most PC compatible computers, XT and AT 286/386/486 and above, including some portables, can accommodate and provide power for this board. When installing the board in an 8 bit slot, ensure that the extension connector does not foul any baseboard components. 2.5 Backing up the Software Diskette Make a backup copy of the software diskette is made and store the original in a safe place. The diskette can be copied onto a blank diskette and/or the software copied onto the hard disk. Refer to the DOS manual for information on disk copying. Always use the working copy. 2.6 Configuration Switch and Jumper Settings Before mounting this board in the host computer, the configuration needs to be set to the user's requirements. Setting is by means of on-board in-line switches and pluggable jumpers whose functions are described below. The factory set configuration will suffice for many users needs. 2.7 Base Address Selection Each port has a base address and the port occupies eight contiguous register locations above and including the selected port base address. Each PC231/PC241 Series board in a system can be set to provide a pattern of port addresses within the range 160 to 7F816. The only restrictions on addresses within the designated ranges are those brought about by pre-allocations or conflicting port assignments, the user must therefore ensure that:- 1. No two channels on more than one PC231/PC241 Series board are set to the same port base address. 2. No channel is set to an address already utilised or allocated within the host computer, nor by any other peripheral. Page 6 PC231/PC241 Series

13 To assist the user in choosing suitable base addresses for each channel, the ports normally allocated to communication channels COM1 through COM8 and the standard I/O map are tabled in sections and Many computers already have at least one serial port built in, and this port is normally allocated the COM1 address. If two ports are in-built, then they will normally be set at COM1 and COM2 addresses. In this situation, if the address map incorporating these COM addresses is required for the port base addresses on the PC231/PC241 Series board, potential contention problems can be solved by disabling the in-built serial ports or disabling channels 1 and/or 2 of the PC231/PC241 Series board. Refer to the host PC or I/O adaptor instruction manual for information on disabling the PC ports or paragraph for information on disabling the PC231/PC241 Series board channels 1 and/or 2. DOS 5.0 and later includes a command to determine the status of installed serial communications ports. With the PC231/PC241 Series board removed, at the C: prompt, enter: MSD.EXE <Return> Choose: COM PORTS and the status of all ports occupying COM1 to COM4 will be shown in a table Factory Settings for the Channel Base Addresses Only four serial communications port addresses are allocated in the PC I/O map. More than four ports are often required, and the list below shows the addresses usually allocated by hardware and software manufacturers to the serial ports COM1 to COM8. The PC231/PC241 Series board is factory configured to use these eight standard COM port settings: Channel Port I/O Address Channel Port I/O Address 1 COM1 3F8 5 COM COM2 2F8 6 COM COM3 3E8 7 COM COM4 2E8 8 COM User Configured Base Addresses The required base addresses are set up by means of five poles of the in-line switch bank Sw4. Grouping is arranged so that channels 1 to 4 of the board may be set to one of four predetermined patterns of four addresses and channels 5-6 set to another one of four predetermined patterns of four addresses. Using pole 1, all eight channels can be further offset by to provide another set of 32 selectable port base addresses. This arrangement allows a total of 64 discrete channel base addresses to be utilised without mutual conflict across a total eight PC231/PC241 Series boards. The base address switch settings are illustrated in three tables, and the selection method will depend on the user's needs. Switch Sw4 can be located by reference to the appropriate layout drawing shown in Appendix C. The eight locations above each base are automatically allocated to the selection of individual registers of the Universal Asynchronous Receiver/Transmitter (UART aka ACE), used for each channel. Details of the register offsets are given in Chapter 5. PC231/PC241 Series Page 7

14 FIGURE 2.1 STANDARD BASE ADDRESSES FOR UP TO EIGHT BOARDS The table shown in figure 2.1 should be used for the standard base address settings of up to eight boards. The first row shows the default board setting which sets up the eight channels at the industry standard communications port addresses. FIGURE 2.2 A and 2.2 B CHANNEL BASE ADDRESSES These tables show the combinations that may be set up for any group of four addresses in combination with another group of four. Groups in figure 2.2 A cannot be mixed with groups in figure 2.2 B. Use this table when less than eight boards are to be installed, and it is necessary to manoeuvre the selected addresses around other adaptor I/O space. FIGURE 2.3 ADDRESS SWITCH SETTING TABLE The table in figure 2.3 shows the addresses selected for all the possible switch combinations. Use this table to look up the eight channel addresses selected when the switch setting is known. The shaded rows indicate the settings shown in figure 2.1 for the simplest combinations for up to eight boards (64 channels). The other combinations are possible, and are provided to allow the selected addresses to be manoeuvred Simple Set-up of Base Addresses for up to Eight Boards The table below shows how to set up the standard base address selections for up to eight PC231(i) or PC241(i) serial communications boards. Board Number Chan 1 Chan 2 Chan 3 Chan 4 Chan 5 Chan 6 Chan 7 Chan 8 Switch Sw4 Settings and Notes ON 1 3F8 2F8 3E8 2E A0 1A8 1B0 1B8 4 2A0 2A8 2B0 2B F8 6F8 7E8 6E A0 5A8 5B0 5B8 8 6A0 6A8 6B0 6B Default board setting. If conflict occurs with inbuilt Coms ports, see para ON ON ON ON ON ON ON FIGURE 2.1 STANDARD BASE ADDRESSES FOR UP TO EIGHT BOARDS Page 8 PC231/PC241 Series

15 Sw4 Poles Group Nº Switch Sw4 Pole 1 OFF BASE ADDRESS RANGE 160 to 3F8 Port Base Address Board Channel Nº (Hex) (1 to 8) 0 0 X X X1 2A0 1 2A8 2 2B0 3 2B X1 3F8 (COM1) 1 2F8 (COM2) 2 3E8 (COM3) 3 2E8 (COM4) 4 0 X X2 1 1A0 5 1A8 6 1B0 7 1B8 8 0 X X (COM5) (COM6) (COM7) (COM8) 8 Sw4/1-7 Setting Any combination of one upper selection and one lower selection is permissible. FIGURE 2.2 A CHANNEL BASE ADDRESS TABLE 160-3F8 ON ON ON ON ON ON ON ON X1 = Select Sw4/4-5 settings from lower section of table X2 = Select Sw4/2-3 settings from upper section of table PC231/PC241 Series Page 9

16 Sw4 Poles Group Nº Switch Sw4 Pole 1 ON BASE ADDRESS RANGE 560 to 7F8 Port Base Address Board Channel Nº (Hex) (1 to 8) 1 0 X X X3 6A0 1 6A8 2 6B0 3 6B X3 7F8 1 6F8 2 7E8 3 6E8 4 1 X X4 1 5A0 5 5A8 6 5B0 7 5B8 8 1 X X Sw4/1-7 Setting Any combination of one upper selection and one lower selection is permissible. FIGURE 2.2 B CHANNEL BASE ADDRESS TABLE 560-7F8 ON ON ON ON ON ON ON ON X3 = Select Sw4/4-5 settings from lower section of table X4 = Select Sw4/2-3 settings from upper section of table Page 10 PC231/PC241 Series

17 Sw4 CHANNEL BASE ADDRESSES SETTING Chan 1 Chan 2 Chan 3 Chan 4 Chan 5 Chan 6 Chan 7 Chan x x A0 1A8 1B0 1B x x x x A0 1A8 1B0 1B x x x 2A0 2A8 2B0 2B x 2A0 2A8 2B0 2B8 1A0 1A8 1B0 1B x 2A0 2A8 2B0 2B x 2A0 2A8 2B0 2B x 3F8 2F8 3E8 2E x 3F8 2F8 3E8 2E8 1A0 1A8 1B0 1B x 3F8 2F8 3E8 2E x 3F8 2F8 3E8 2E x x A0 5A8 5B0 5B x x x x A0 5A8 5B0 5B x x x 6A0 6A8 6B0 6B x 6A0 6A8 6B0 6B8 5A0 5A8 5B0 5B x 6A0 6A8 6B0 6B x 6A0 6A8 6B0 6B x 7F8 6F8 7E8 6E x 7F8 6F8 7E8 6E8 5A0 5A8 5B0 5B x 7F8 6F8 7E8 6E x 7F8 6F8 7E8 6E z z z z z 0 1 x Inhibit 1 z z z z z z z z z z z z 1 0 x z Inhibit 2 z z z z z z z z z z z 0 0 x Inhibit 1 Inhibit 2 z z z z z z x = Inapplicable (Interrupt group setting) z = Switch settings from rows above FIGURE 2.3 ADDRESS SWITCH SETTING TABLE PC231/PC241 Series Page 11

18 2.7.4 Channels 1 and/or 2 Inhibit If a base address group 0 3 x is selected, then channels 1 and 2 are located at the COM1 and COM2 addresses 3F8 and 2F8 respectively. These are the I/O addresses normally allocated to communications ports that may be built into the host PC. A conflict will occur if an attempt is made to use either or both of these addresses simultaneously by two ports. To overcome this potential problem, the PC built-in communications ports can normally be disabled, but if it is impossible or undesirable to do this, then channels 1 and/or 2 of the PC231/PC241 board may be inhibited using two poles of switch Sw4. Channel 1 Inhibit Channel 2 Inhibit Switch Sw4 pole 6 enables or disables channel 1 of the PC231/PC241. The switch is ON (UP) to enable channel 1 and OFF (DOWN) to disable the channel. The factory default setting is ON. Switch Sw4 pole 7 enables or disables channel 2 of the PC231/PC241. The switch is ON (UP) to enable channel 2 and OFF (DOWN) to disable the channel. The factory default setting is ON PC I/O Map The standard PC/AT I/O map assignments are listed in figure 2.4 below. I/O addresses to 0FF16 are reserved for the PC system board use. Hex Range Usage 1F0-1FF Hard Disc (AT) F Game/Control F Reserved B Bus Mouse 23C - 23F Alt. Bus Mouse F Parallel Printer 2B0-2DF EGA 2E0-2E7 GPIB (AT) 2E8-2EF Serial Port COM4 2F2-2F7 IRQ 9, 2-7 Re-arm 2F8-2FF Serial Port COM F Prototype Card F Network F Parallel Printer F SDLC 3A0-3AF SDLC 3B0-3BB MDA 3BC - 3BF Parallel Printer 3C0-3CF EGA 3D0-3DF CGA 3E8-3EF Serial Port COM3 3F0-3F7 Floppy Disc 3F8-3FF Serial Port COM1 6F2-6F7 IRQ Re-arm FIGURE 2.4 pc i/o map assignments Page 12 PC231/PC241 Series

19 2.8 Interrupt Level Selection Each serial communications channel generates an interrupt output (when enabled by the UART interrupt enable register) whenever a receiver error, receiver data available, transmitter empty or modem status condition flag is detected. This interrupt signal from each channel can be assigned to one of a group of four mutually inclusive IRQ levels and the required level for each channel is selected by the code of a two pole switch. Shared or non-shared interrupts comply with the ISA standard and the type of operation for each channel is selected by a pole of another switch. Two groups of four levels are selectable for the entire board and a single board level switch (Sw4/8) selects one of the two groups for all eight channels. These two groups are: IRQ 3, 4, 5 and 7 or IRQ 10, 11, 12 and Factory Settings for the IRQ Levels The interrupt level selection switches are set at the factory to interrupt group IRQ 3, 4, 5 and 7 (Switch Sw4/8 OFF), and individual channels set as in the table below. CHANNEL Nº IRQ SETTING SHARING STATUS Sw3 and Sw2 Sw1 Channel 1 IRQ 4 Sw3/ 1 OFF - 2 ON Shared Sw1/1 ON Channel 2 IRQ 3 Sw3/ 3 OFF - 4 OFF Shared Sw1/2 ON Channel 3 IRQ 4 Sw3/ 5 OFF - 6 ON Shared Sw1/3 ON Channel 4 IRQ 3 Sw3/ 7 OFF - 8 OFF Shared Sw1/4 ON Channel 5 IRQ 5 Sw2/ 1 ON - 2 OFF Shared Sw1/5 ON Channel 6 IRQ 7 Sw2/ 3 ON - 4 ON Shared Sw1/6 ON Channel 7 IRQ 5 Sw2/ 5 ON - 6 OFF Shared Sw1/7 ON Channel 8 IRQ 7 Sw2/ 7 ON - 8 ON Shared Sw1/8 ON User Configured IRQ Levels The user must decide which interrupt level to select for each channel and set the required code for that IRQ on switches Sw4/8 (group selection) and Sw3 or Sw2 (individual selection). Shared or non-shared operation of the interrupts on each channel should also be selected at this stage and set up on switch Sw1. Interrupt operations are discussed in chapter 6 and the interrupt registers are described in chapter 5. When the switch has been set up for a particular IRQ on channel 1, that selected IRQ level is allocated to channel 1, and similarly another IRQ level can be selected for channel 2. If nonshared interrupts are selected, then the same IRQ level cannot be selected for both channels, unless the interrupts on one channel have been disabled. Interrupts are disabled on power up reset or by writing to the Modem Control Register (Bit 3=0). If shared interrupts are selected, then the same IRQ level may be set for several channels and can be shared with other boards in the PC that similarly handle shared interrupts. Note that shared interrupts are only supported by compliant AT/286 and above compatible computers. PC231/PC241 Series Page 13

20 Shared and non-shared operation may be mixed, for example. two channels may have individual non-shared IRQ levels and the remaining six channels shared on another IRQ level Interrupt Group Selection Two groups of four interrupt request (IRQ) levels are available for each board, and once a group has been selected, each channel can be individually set to any level in that group. Selection of the required group is made by pole 8 (right hand) of switch Sw4, the other seven poles being used for base address selection and channel inhibits as described in paragraph 2.7. Switch Sw4 can be located by reference to the appropriate layout drawing shown in appendix C. The higher group is not available when the board is plugged into an ISA 8 bit slot. ON Switch Sw4, pole 8 OFF (Switch down) Interrupt group IRQ 3, 4, 5 and 7 selected for the entire board ON Switch Sw4, pole 8 ON (Switch up) Interrupt group IRQ 10, 11, 12 and 15 selected for the entire board FIGURE 2.5 SWITCH SELECTION OF INTERRUPT GrOUP Individual Channel Interrupt Level Selection Each channel may have an individual IRQ level set for that channel, but as there are four levels available for the eight channels, some channels must share common IRQ levels. Two poles of a switch select the required level for each channel. Figure 2.6 below shows the positions of the switches for the individual channels 1 to 8, and the diagrams illustrate the factory default settings. Switches Sw3 and Sw4 can be located by reference to the appropriate layout drawing shown in appendix C. A full list of settings is shown in figure 2.7. SW3 SET IRQ CHN 1-4 SW2 SET IRQ CHN 5-8 ON ON CHAN 4 Poles 7-8 CHAN 3 Poles 5-6 CHAN 2 Poles 3-4 CHAN 1 Poles 1-2 CHAN 8 Poles 7-8 CHAN 7 Poles 5-6 CHAN 6 Poles 3-4 CHAN 5 Poles 1-2 FIGURE 2.6 INDIVIDUAL INTERRUPT SWITCH POSITIONS The table shown in figure 2.7 below provides the switch setting information for all possible IRQ levels that may be configured for each channel. Either column 2 or column 3 will apply according to the group selected by Sw 4/8. IRQ levels from the two groups cannot be mixed. Page 14 PC231/PC241 Series

21 Channel Number Group 3, 4, 5, 7 (Sw4/8 OFF) Group 10, 11, 12, 15 (Sw4/8 ON) Sw3 or Sw2 Setting (X = Other Channels) Channel 1 IRQ 3 IRQ 10 Sw3 00XXXXXX IRQ 4 IRQ 11 Sw3 01XXXXXX IRQ 5 IRQ 12 Sw3 10XXXXXX IRQ 7 IRQ 15 Sw3 11XXXXXX Channel 2 IRQ 3 IRQ 10 Sw3 XX00XXXX IRQ 4 IRQ 11 Sw3 XX01XXXX IRQ 5 IRQ 12 Sw3 XX10XXXX IRQ 7 IRQ 15 Sw3 XX11XXXX Channel 3 IRQ 3 IRQ 10 Sw3 XXXX00XX IRQ 4 IRQ 11 Sw3 XXXX01XX IRQ 5 IRQ 12 Sw3 XXXX10XX IRQ 7 IRQ 15 Sw3 XXXX11XX Channel 4 IRQ 3 IRQ 10 Sw3 XXXXXX00 IRQ 4 IRQ 11 Sw3 XXXXXX01 IRQ 5 IRQ 12 Sw3 XXXXXX10 IRQ 7 IRQ 15 Sw3 XXXXXX11 Channel 5 IRQ 3 IRQ 10 Sw2 00XXXXXX IRQ 4 IRQ 11 Sw2 01XXXXXX IRQ 5 IRQ 12 Sw2 10XXXXXX IRQ 7 IRQ 15 Sw2 11XXXXXX Channel 6 IRQ 3 IRQ 10 Sw2 XX00XXXX IRQ 4 IRQ 11 Sw2 XX01XXXX IRQ 5 IRQ 12 Sw2 XX10XXXX IRQ 7 IRQ 15 Sw2 XX11XXXX Channel 7 IRQ 3 IRQ 10 Sw2 XXXX00XX IRQ 4 IRQ 11 Sw2 XXXX01XX IRQ 5 IRQ 12 Sw2 XXXX10XX IRQ 7 IRQ 15 Sw2 XXXX11XX Channel 8 IRQ 3 IRQ 10 Sw2 XXXXXX00 IRQ 4 IRQ 11 Sw2 XXXXXX01 IRQ 5 IRQ 12 Sw2 XXXXXX10 IRQ 7 IRQ 15 Sw2 XXXXXX11 0 = OFF (Down) 1 = ON (Up) X = Other Channels FIGURE 2.7 INDIVIDUAL INTERRUPT SWITCH SETTINGS Selection of Shared or Non-Shared Operation Each channel may be selected to either share its interrupt level with other channels, or to use non-shared operation, when the selected IRQ level applies to that channel only. The sharing status for each channel is set up by the eight poles of switch Sw 1. Shared and non-shared status may be mixed as required. PC231/PC241 Series Page 15

22 Sharing operation is switched ON when the individual pole is in the up (ON) position. When switched down (OFF), the channel is set up for non-shared operation. ENABLE SHARED INTs CHAN SW1 ON Channel Number Sw 1 Pole Shared Non- Shared Chan 8 Sw 1/8 ON OFF Chan 7 Sw 1/7 ON OFF Chan 6 Sw 1/6 ON OFF Chan 5 Sw 1/5 ON OFF Chan 4 Sw 1/4 ON OFF Chan 3 Sw 1/3 ON OFF Chan 2 Sw 1/2 ON OFF Chan 1 Sw 1/1 ON OFF FIGURE 2.8 INTERRUPT SHARING SELECTION IRQ Assignments The user must ensure that no contention exists when selecting an IRQ level. The normal allocation of hardware interrupt levels is tabled below. PC231/241(i) Host PC Host PC Host PC Selected IRQ Interrupt Description IRQ Level Name Number (hex) of Usage 0 8 Timer Not available on the 1 9 Keyboard Bus Connectors IRQ 2 A Int IRQ 3 B COM or SDLC IRQ IRQ 4 C COM or SDLC available on 5 IRQ 5 D LPT 8 and 16 bit slots IRQ 6 E Floppy Disk 7 IRQ 7 F LPT IRQ 8 70 Real Time Clock IRQ 9 71 Re-directed to IRQ2 10 IRQ10 72 Unassigned IRQ IRQ11 73 Unassigned available on 12 IRQ12 74 Unassigned (or bus-mouse) 16 bit slots IRQ13 75 Co-processor only IRQ14 76 Hard Disk 15 IRQ15 77 Unassigned FIGURE 2.9 INTERRUPT LEVEL ASSIGNMENTS Page 16 PC231/PC241 Series

23 2.9 RS-422/485 Full Duplex / Half Duplex Operation An RS-422/485 port on a PC241 or PC241i can be used in either full duplex (simultaneous transmission and reception over two independent wire pairs) or half duplex (sequential transmission or reception over a single wire pair). In full duplex operation, a separate transmitter and receiver circuit is employed, and in this mode the transmitter can be left in its enabled state at all times. In half duplex receive operation, the transmitter must be disabled by switching to its high impedance state to allow reception of data over the same serial lines. The RS-422/485 ports are provided with all the data input/output terminals required for full duplex operation. If half duplex operation is required, then external and internal configuration changes must be considered. Also check that the termination resistor, paragraph 2.10, is correctly connected or disconnected for the requirements of the network Selection of Full/Half Duplex A single jumper for each channel is individually set for full or half duplex operation. The settings must be made in accordance with the following table. Default settings are all channels full duplex, but the jumper links are provided (hung on one pin) for half duplex operation. It is important that the echo jumper is out for full duplex operation (see para 2.9.2) and the appropriate connector wiring for full or half duplex is properly implemented. The external wiring connections are discussed in paragraph 3.3. CHANNEL JUMPER FULL DUPLEX HALF DUPLEX Channel 1 J112 Out In Channel 2 J122 Out In Channel 3 J132 Out In Channel 4 J142 Out In Channel 5 J152 Out In Channel 6 J162 Out In Channel 7 J172 Out In Channel 8 J182 Out In FIGURE 2.10 JUMPER SETTING FOR FULL/HALF DUPLEX Selection of Local Echo On/Off in Half Duplex Operation The factory default configuration of jumpers J111, J121 through J181 causes the transmitted data to be echoed to the receiver in half duplex operation. If this echo is not required, continuous operation of the receiver must be inhibited by inserting the appropriate jumper. This change ensures that the RS-485 receiver is enabled/disabled in opposite phase to the transmitter. Default settings are all channels echo ON (full duplex), but the jumper links provided must be inserted for echo OFF operation. The Local Echo operation provided with some serial communications programs is a separate facility, and should normally be turned off. For full duplex operation, the echo jumper must be in its default condition (out) for the receiver to be continuously enabled. Echo is not appropriate to full duplex operation. PC231/PC241 Series Page 17

24 CHANNEL JUMPER ECHO ON (Full/Half duplex) ECHO OFF (Half duplex only) Channel 1 J111 Out In Channel 2 J121 Out In Channel 3 J131 Out In Channel 4 J141 Out In Channel 5 J151 Out In Channel 6 J161 Out In Channel 7 J171 Out In Channel 8 J181 Out In FIGURE 2.11 JUMPER SETTING FOR ECHO IN HALF DUPLEX MODE 2.10 Transmission Line Termination RS-232 operations are normally point-to-point over short distances and require no special termination of the control and data lines. RS-422/485 operations use transmission line techniques and often operate over longer distances when line termination is important, and as the requirement is system dependent, a facility is available on the PC241(i) boards to terminate as required Termination Resistors for RS-422/485 Receivers Operation of RS-422/485 systems requires that the lines be terminated at the final receiver. The simplest termination is by a line-to-line resistor, and provision is made to connect this 120Ω terminator on the data and control inputs of each RS-422/485 channel. The RS422/485 CTS control line receivers are permanently terminated and the data input terminator resistors can be disconnected by removal of a jumper for each channel. Jumpers J110, J120 through J180 etc are factory fitted, and should be retained in position as required to terminate the following differential receiver line pairs:- RECEIVER Channel 1 Rx Data Terminator Channel 2 Rx Data Terminator Channel 3 Rx Data Terminator Channel 4 Rx Data Terminator Channel 5 Rx Data Terminator Channel 6 Rx Data Terminator Channel 7 Rx Data Terminator Channel 8 Rx Data Terminator JUMPER J110 J120 J130 J140 J150 J160 J170 J180 Further notes on RS-422 and RS-485 operation are given later in Chapter 4, 'Using the Serial Communications Boards' Page 18 PC231/PC241 Series

25 2.11 Switch and Jumper Factory Settings Summary The PC231(i) and PC241(i) Series boards can be reset to their factory defaults by re-configuring the board switches and jumpers according to the following tables. Switch Function Switch Settings Sw1 Enable Shared Interrupts 1-on 2-on 3-on 4-on 5-on 6-on 7-off 8-on Sw2 Set IRQ on 2-off 3-on 4-on 5-on 6-off 7-on 8-on Sw3 Set IRQ off 2-on 3-off 4-off 5-off 6-on 7-off 8-off Sw4 Base Address and IRQ Group 1-off 2-on 3-on 4-on 5-on 6-on 7-on 8-off Jumper Function PC231 (i) PC241(i) J112 Channel 1 Full Duplex N/A Out J111 Channel 1 Echo N/A Out J110 Channel 1 Termination N/A In J122 Channel 2 Full Duplex N/A Out J121 Channel 2 Echo N/A Out J120 Channel 2Termination N/A In J132 Channel 3 Full Duplex N/A Out J131 Channel 3 Echo N/A Out J130 Channel 3 Termination N/A In J142 Channel 4 Full Duplex N/A Out J141 Channel 4 Echo N/A Out J140 Channel 4Termination N/A In J152 Channel 5 Full Duplex N/A Out J151 Channel 5 Echo N/A Out J150 Channel 5 Termination N/A In J162 Channel 6 Full Duplex N/A Out J161 Channel 6 Echo N/A Out J160 Channel 6Termination N/A In J172 Channel 7 Full Duplex N/A Out J171 Channel 7 Echo N/A Out J170 Channel 7 Termination N/A In J182 Channel 8 Full Duplex N/A Out J181 Channel 8 Echo N/A Out J180 Channel 9Termination N/A In FIGURE 2.12 FACTORY SWITCH AND jumper setting summary PC231/PC241 Series Page 19

26 2.12 Software Installation A test program is supplied with the PC231 and PC241 Series board and testing by the use of this software is discussed in section 4.4. The Terminal program supplied with Windows is compatible with the PC231/241 Series boards and is useful for testing and operation using non-shared interrupts on COM1 to COM4 channels. Operational software is not supplied with the card, but a choice of suitable software packages is available from Amplicon Liveline Ltd to allow easy integration of interrupt driven serial communications into the user's application. The Amplicon 'COMBIOS for DOS' and COMBIOS for Windows are communications support toolkits which allow add-on serial ports to many language compilers. Demonstration versions of these two packages are included on the distribution diskette. The board will operate in conjunction with many commercially available communications and data acquisition packages that support RS-232, RS-422 or RS-485 serial operations. The software should be installed according to the supplier's instructions, and due note should be taken of the required settings for the communications channels, and the board configuration settings made to correspond. The following software limitations should be remembered when allocating COM channels:- MS-DOS 3.2 and below provides support for the first two serial ports only, COM1 and COM2. MS-DOS 3.3 and above supports COM1, COM2, COM3 and COM4 but expects COM1/COM3 and COM2/COM4 to be assigned interrupts IRQ 4 and IRQ3 respectively. Windows supports COM1, COM2, COM3 and COM4 on separate non-shared interrupt levels. Other operating systems allow the use of more than two ports. Check the instructions. Most BASIC language interpreters/compilers only support COM1 and COM Installation Testing Many applications packages include a self test feature, and when the hardware and software have been satisfactorily installed, any such test should be performed to check correct operation. If no self test is available, or a problem occurs, see the later section 4.4, 'Testing and Troubleshooting'. Page 20 PC231/PC241 Series

27 3 MAKING THE CONNECTIONS This chapter describes the signal and control connections that the user must make between the PC231(i) or PC241(i) board and any external serial communications devices. These input/output connections can be made directly through the multi-way D type connector protruding from the PC adaptor slot corresponding to the chosen board position, or by the use of standard 9 or 25 way connectors mounted on an optional, external accessory panel. For completeness of information, the standard PC back-plane bus connections are also shown in figure 3.9. Chan PC231(i)/PC242(i) Pin Common Protective Ground 1 Common Power Ground 40 Common +5 VDC Output 21 Chan PC231(i) PC241(i) Pin 2 SGND(i) TX-B 4 2 RI RX-B' 43 2 DTR TX-A 24 2 CTS RX-A' 63 2 TXD RTS-A 5 2 RTS CTS-B' 44 2 RXD RTS-B 25 2 DSR CTS-A' 64 2 DCD SGND(i) 6 Chan PC231(i) PC241(i) Pin 4 SGND(i) TX-B 28 4 RI RX-B' 67 4 DTR TX-A 9 4 CTS RX-A' 48 4 TXD RTS-A 29 4 RTS CTS-B' 68 4 RXD RTS-B 10 4 DSR CTS-A' 49 4 DCD SGND(i) 30 Chan PC231(i) PC241(i) Pin 6 SGND(i) TX-B 13 6 RI RX-B' 52 6 DTR TX-A 33 6 CTS RX-A' 72 6 TXD RTS-A 14 6 RTS CTS-B' 53 6 RXD RTS-B 34 6 DSR CTS-A' 73 6 DCD SGND(i) 15 Chan PC231(i) PC241(i) Pin 8 SGND(i) TX-B 37 8 RI RX-B' 76 8 DTR TX-A 18 8 CTS RX-A' 57 8 TXD RTS-A 38 8 RTS CTS-B' 77 8 RXD RTS-B 19 8 DSR CTS-A' 58 8 DCD SGND(i) Pin Chan PC231(i) PC241(i) 60 1 SGND(i) TX-B 2 1 RI RX-B' 41 1 DTR TX-A 22 1 CTS RX-A' 61 1 TXD RTS-A 3 1 RTS CTS-B' 42 1 RXD RTS-B 23 1 DSR CTS-A' 62 1 DCD SGND(i) Pin Chan PC231(i) PC241(i) 45 3 SGND(i) TX-B 26 3 RI RX-B' 65 3 DTR TX-A 7 3 CTS RX-A' 46 3 TXD RTS-A 27 3 RTS CTS-B' 66 3 RXD RTS-B 8 3 DSR CTS-A' 47 3 DCD SGND(i) Pin Chan PC231(i) PC241(i) 69 5 SGND(i) TX-B 11 5 RI RX-B' 50 5 DTR TX-A 31 5 CTS RX-A' 70 5 TXD RTS-A 12 5 RTS CTS-B' 51 5 RXD RTS-B 32 5 DSR CTS-A' 71 5 DCD SGND(i) Pin Chan PC231(i) PC241(i) 54 7 SGND(i) TX-B 35 7 RI RX-B' 74 7 DTR TX-A 16 7 CTS RX-A' 55 7 TXD RTS-A 36 7 RTS CTS-B' 75 7 RXD RTS-B 17 7 DSR CTS-A' 56 7 DCD SGND(i) Pin Chan PC231(i)/PC241(i) 78 Common +5 VDC Output 20 Common Power Ground 59 Common Protective Ground FIGURE WAY I/O CONNECTOR PIN DESIGNATIONS PC231/PC241 Series Page 21