Specifications

2240 Fiber Optic Modem

Data Set Ready (DSR) and Test Mode (TM) are local status leads and follow the functions

described in RS-232D. DSR typically indicates that the modem is ready to handle transmit

data. During loopbacks, the behavior of this signal is dependent on the position of the DSR

jumper (see description of DSR jumper). TM indicates that a loopback is active on one or

both modems.

Local Loopback (LL) and Remote Loopback (RL) are loopback control leads and perform

the same functions as the 2240 front panel LOOP switch LOC and REM positions. LL and

RL are interface signal inputs which can be used to activate the LOC or REM loop func-

tions.

Table 4-A.

RS-232D

Pinouts

Pin RS-232D Direction

Number Pin Name

(abbrev) Full Name

1 PG Protective Ground -

2 TD Transmit Data to modem

3 RD Receive Data from modem

4 RTS Request to Send to modem

5 CTS Clear to Send from modem

6 DSR DCE Ready from modem

7 SG Signal Ground -

8 DCD Receive Line Sig. Det. from modem

12 SDCD Secondary Line Sig. Det. from modem

13 SCTS Secondary CTS from modem

14 STD Secondary TD to modem

15 SCT Transmit Clock from modem

16 SRD Secondary RD from modem

17 SCR Receive Clock from modem

18 LL Local Loopback to modem

19 SRTS Secondary RTS to modem

20 DTR DTE Ready to modem

21 RL Remote Loopback to modem

22 RI Ring Indicator from modem

23 DSRS Data Signal Rate Selector to modem

24 SCTE Transmit Clock External to modem

25 TM Test Mode from modem