ND-20292
CHAPTER 2
APRIL, 1990
RS-232C MALE RS-232C MALE
CONNECTOR CONNECTOR
7 SG . . 7 SC
2 TXD . TXD
3 Rx5 *-: RXD
4 RTS l . 4 RTS
Q
5 CTS . . 5 CTS
TO MODEM 6 DSR . l 6 DSR
8 DCD . . 8 DCD
20 DTR . - 20 DTR
11 PB .
TO DTA-E
UNIT

NOTE

1: Switch settings on DTA-E Unit are as

follows:

SW l-2 (RS) . . . . . . . ON

SW 3-3& 8 . . . . . . . . . . . ON

All other Pins . . . . . . . . OFF

NOTE

2: If pin 8 (CD) from the modem is high,

MBlD2, LK3 must be OFF.

Figure 200-55 Wiring Connections of RS-232C Null Modem Cable for Connecting a Modem to a DTA-E

(Rev. 2 or higher) Unit.

EIA
PIN NO.
1
2
3
4
5
Is
7
12
14
16
21
22
&
24
25
r
I
-
SIGNAL SIGNAL
DESIGNATION DESIGNATION
L TELEPHONE LINE LAMP CONTROL
MB1 MAKE BUSY RELAY CONTACTS IN MODEM
MB MAKE BUSY RELAY CONTACTS IN MODEM
LG GROUND RETURN FOR LAMP CIRCUIT
TD TALK/DATA SWITCH CONTACTS IN TELEPHONE (WITH TDG) (POWER RELAY CONTACT)
T TELEPHONE LINE TIP
R TFl FPHONF LINF RING
RD RING DETECT CONTACTS (TO GROUND) IN MODEM
C DATA MODE CONTACTS (TO GROUND) IN MODEM
Dl DATA MODE CONTACTS (TO GROUND) FROM ACU
Tl TELEPHONE SET TIP
RI TELEPHONE SET RING
A CONTACTCLOSURE INDICATING THAT MODEM ORTELEPHONE IS HOLDING THE LINE
Al CONTACTCLOSURE INDICATING THAT MODEM ORTELEPHONE IS HOLDING THE LINE
TDG GROUND RETURN FOR TD SWITCH (SEE PIN 5) (POWER RELAY CONTACT)

Figure 200-56 Data Set Modem (Non Hayes Compatible Modem) Telephone or ACU Interface

200 - 46