Black Box 32144 Manual page 27

MODEM 32144
Table C-1. Pin Assignments—DB25 TIA/EIA Interface Connector
Pin Function
1 Frame ground—not connected
2 Transmit (send) data (TD)
3 Received data (RD)
4 Request to send (RTS)
5 Clear to Send (CTS)
6 Data Set (modem) Ready (DSR)
7 Signal ground (SG)
8 Carrier detect (CD)
9 Testing voltage, +10V
10 Testing voltage, -10V
15 Transmit clock (TC)
17 Receive clock (RC)
18 Analog loopback (ALB) control
20 Data terminal ready (DTR)
21 Remote digital loopback (RDL)
control
1
22 Ring indicator (RI)
24 External transmit clock (XTC)
25 Test mode indicator (TM)
1 + voltage activates indicated loopback test (but only if ALB-DTE Ctrl'ed or RDL-
DTE Ctrl'ed option is enabled);—voltage disables test.
2 Alternately, pin 25 may be used for analog loopback (ALB) control.
178
Designation
EIA
AA
BA
BB
CA
CB
CC
AB
CF
+P
-P
DB
DD
1 CN
CD
CN
CE
DA
2 CN
ITU-T LCD
101
103 TD
104 RD
105 RS
106 CS
107 MR
102
109 CD
114
115
108/2 TR
125 R
113
TM
Source
DTE
Modem
DTE
Modem
Modem
Ground
Modem
Modem
Modem
Modem
Modem
DTE
DTE
DTE
Modem
DTE
Modem