tions Command State (Section 5). If the carriage returns are not received within the 40 seconds, the CR10 "hangs up".

TABLE 6.7-1. SC32A Pin Description

ABR

=

Abbreviation for the function name

PIN

=

Pin number

O

=

Signal Out of the SC32A to a

 

 

peripheral

I= Signal Into the SC32A from peripheral

25-PIN FEMALE PORT:
PIN #

I/O

ABBREVIATION

1

 

GROUND

2

I

TX

3

O

RX

4

I

RTS (POWER)

5

O

CTS

6

O

DSR

7

 

GROUND

8

O

DCD

20

I

DTR (POWER)

9-PIN MALE PORT:

PIN #

 

ABBREVIATION

1

 

+5V INPUT

2

 

GROUND

3

 

RING

4

 

RX

5

 

ME

6

 

SDE

9

 

TX

NOTE: The SC32A has a jumper, which when used, passes data only when the ME line is high and the SDE line is low. The function of the jumper is to block data sent to SDs from being received by a computer/terminal used to initiate data transfer. Synchronous data will appear as garbage characters on a computer/terminal.

6.7.2 COMPUTER/TERMINAL REQUIREMENTS

Computer/terminal peripherals are usually configured as Data Terminal Equipment (DTE). Pins 4 and 20 are used as handshake lines, which are set high when the serial port is enabled. Power for the SC32A RS232 section is taken from these pins. For equipment configured as DTE (see Table 6.7-2) a direct ribbon cable connects the computer/terminal to the SC32A. Clear to Send (CTS) pin 5, Data

SECTION 6. 9-PIN SERIAL INPUT/OUTPUT

Set Ready (DSR) pin 6, and Received Line Signal Detect (RLSD) pin 8 are held high by the SC32A (when the RS232 section is powered) which should satisfy hardware handshake requirements of the computer/terminal.

Table 6.7-2 lists the most common RS232 configuration for Data Terminal Equipment.

TABLE 6.7-2. DTE Pin Configuration

PIN

=

25-pin connector number

ABR =

Abbreviation for the function name

O

=

Signal Out of terminal to another device

I

=

Signal Into terminal from another device

PIN

 

ABR

I/O

FUNCTION

2

 

TD

O

Transmitted Data: Data

 

 

 

 

is transmitted from the

 

 

 

 

terminal on this line.

3

 

RD

I

Received Data: Data is

 

 

 

 

received by the terminal

 

 

 

 

on this line.

4

 

RTS

O

Request to Send: The

 

 

 

 

terminal raises this line

 

 

 

 

to ask a receiving device

 

 

 

 

if the terminal can

 

 

 

 

transmit data.

5

 

CTS

I

Clear to Send: The

 

 

 

 

receiving device raises

 

 

 

 

this line to let the

 

 

 

 

terminal know that the

 

 

 

 

receiving device is ready

 

 

 

 

to accept data.

20

 

DTR

O

Data Terminal Ready:

 

 

 

 

The terminal raises this

 

 

 

 

line to tell the modem to

 

 

 

 

connect itself to the

 

 

 

 

telephone line.

6

 

DSR

I

Data Set Ready: The

 

 

 

 

modem raises this line to

 

 

 

 

tell the terminal that the

 

 

 

 

modem is connected to

 

 

 

 

the phone line.

8

 

DCD

I

Data Carrier Detect:

 

 

 

 

The modem raises this

line to tell the terminal that the modem is receiving a valid carrier signal from the phone line.

6-7