Motorola MVME197LE user manual Ring Indicator RI is sent by the modem to

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			EIA-232-D Interconnections
		Table A-1. EIA-232-D Interconnections (Continued)

	Pin	Signal	Signal Name and Description
	Number	Mnemonic	Signal Name and Description
	Number	Mnemonic


	22	RI	RING INDICATOR - RI is sent by the modem to the
			terminal. This line indicates to the terminal that an incoming
			call is present. The terminal causes the modem to answer the
			phone by carrying DTR true while RI is active.

	23	---	Not used.

	24	TXC	TRANSMIT CLOCK - Same as TXC on pin 15.

	25	BSY	BUSY - a positive EIA signal applied to this pin causes the
			modem to go off-hook and make the associated phone busy.

A

Notes

1.High level = +3 to +15 volts. Low level = -3 to -15 volts.

2.EIA-232-D is intended to connect a terminal to a modem. When computers are connected to computers without modems, one of the computers must be configured as a modem and the other as a terminal.

There are several levels of conformance that are appropriate for typical EIA- 232-D interconnections. The bare minimum requirement is the two data lines and a ground. The full version of EIA-232-D requires 12 lines and accommodates automatic dialing, automatic answering, and synchronous transmission. A middle-of-the-road approach is illustrated in Figure A-1.

One set of handshaking signals frequently implemented are RTS and CTS. CTS is used in many systems to inhibit transmission until the signal is high. In the modem applications, TRS is turned around and returned as TRS after 150 microseconds. RTS is programmable in some systems to work with the older type 202 modem (half duplex). CTS is used in some systems to provide flow control to avoid buffer overflow. This is not possible if modems are used. It is usually necessary to make CTS high by connecting it to RTS or to some source of +12 volts such as the resistors shown in Figure A-1. It is also frequently jumpered to an MC1488 gate which has its inputs grounded (the gate is provided for this purpose). Another signal used in many systems is DCD. The original purpose of this signal was to tell the system that the carrier tone from the distant modem was being received. This signal is frequently used by the software to display a message like CARRIER NOT PRESENT to help the user to diagnose failure to communicate. Obviously, if the system is designed properly to use this signal, and it is not connected to a modem, the signal must

MVME197LE/D2

A-3

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Contents MVME197LE/D2 MVME197LERestricted Rights Legend Document Terminology PrefaceBIT Document Title Motorola Publication Number Related DocumentationPage Page Safety Summary Safety Depends on YOU Contents Appendix a List of Figures Xii List of Tables Xiv General Description IntroductionOte FeaturesCharacteristics Specifications SpecificationsMVME197LE Specifications Cooling Requirements FCC Compliance Equipment RequiredSupport Information Hardware Preparation Unpacking InstructionsHardware Preparation and Installation VMEbus Connector P1 Configuration Switch S1 General Information Configuration SwitchesSwitch S1 S1-1 to S1-8 OFF -- All Ones Factory Configuration Connectors Installation InstructionsSwitch S6 MVME197LE Module Installation System Considerations MVME197LE/D2 Hardware Preparation and Installation Reset Switch S3 Controls and IndicatorsAbort Switch S2 Processor Bus Memory Map Front Panel Indicators DS1-DS6Memory Maps Processor Bus Memory Map Local Devices Memory Map Address Range Devices Accessed Port SizeDetailed I/O Memory Maps 110 BusSwitch Register Memory Map100 108Memory Maps ECDM0 ECDM1 ECDM2 ECDM3 ADDR/REGISTER Ecdm CSR Register Memory MapDcam I2C Register Memory Map Dcam I2C Base Address = $C0 default OffsetOperating Instructions Offset VMEchip2 Memory Map Sheet 1Operating Instructions VMEchip2 Memory Map Sheet 2 Global Access BUS Watchdog Timeout Prescaler AdjustOperating Instructions VMEchip2 Memory Map Sheet 3 Operating Instructions VMEchip2 Gcsr Base Address = $FFF40100 VMEchip2 Memory Map Sheet 4Operating Instructions PCCchip2 Memory Map Printer Busy Interrupt Control Register $FFF42034 Printer Fault Interrupt Control Register $FFF42031Printer SEL Interrupt Control Register $FFF42032 Printer PE Interrupt Control Register $FFF42033Base Address Is $FFF45000 Cirrus Logic CD2400 Memory Map Offsets Size AccessCirrus Logic CD2401 Serial Port Memory Map Data Bits Address D31 D16 D15 Address Range Description Size Bytes Accesses may be 8-bit or 32-bit, but not 16-bit11 C710 Scsi Memory Map 12. MK48T08 BBRAM, TOD Clock Memory MapData Bits Address Function 13. Bbram Configuration Area Memory Map14. TOD Clock Memory Map 000000470476 BBRAM, TOD Clock Memory Map0460 5000 VMEbus Accesses to the Local Peripheral BusVMEbus Memory Map 01-W3869B03AMulti-MPU Programming Considerations Local Reset OperationSoftware Initialization User’s Manual MC88110 MPU MVME197LE Functional DescriptionData Bus Structure Functional Description Memory Array Bus Data Bus 256 BusSwitchMC88110 Address Data MUX Address Mezzanine Address BusOnboard Dram Battery Backup RAM and ClockFlash Memory Serial Port Interface VMEbus InterfaceInterfaces Ethernet Interface Printer InterfaceScsi Termination Programmable Tick TimersPeripheral Resources Scsi InterfaceInterrupt Sources Watchdog TimerProcessor Bus Timeout Local Peripheral Bus TimeoutMVME197LE/D2 Functional Description EIA-232-D Interconnections Table A-1. EIA-232-D Interconnections Pin Signal Signal Name and Description Number MnemonicRing Indicator RI is sent by the modem to User’s Manual Figure A-1. Middle-of-the-Road EIA-232-D Configuration Figure A-2. Minimum EIA-232-D Connection Numerics IndexIN-2 IN-3 Index

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