CTC Union ETU-01A - X.21 User Data Channel Connector

Appendix A. I/F Modules
74
May 2011
A.2 X.21 User Data Channel Connector
When the ETU-01A is ordered with an X.21 interface, the physical interface is a 15-pin female D-
Sub type connector wired in accordance with Table A-3.
SIGNAL
FUNCTION
PIN CIRCUIT DIRECTION DESCRIPTION
Protective
Ground
1 Shield
↔
Chassis ground.
May be isolated from Signal Ground.
Signal
Ground
8 G
↔
Common signal ground.
Transmitted
Data
2
9
T(A)
T(B)
To ETU-01A Serial digital data from DTE.
Received
Data
4
11
R(A)
R(B)
Fm ETU-01A
Serial digital data at the output of the ETU-01A
receiver.
Request to
Sent
3
10
C(A)
C(B)
To ETU-01A
A ON signal to the ETU-01A when data
transmission is desired.
Data Carrier
Detect
5
12
I(A)
I(B)
Fm ETU-01A
Constantly ON, except when a loss of the
received carrier signal is detected.
Signal
Timing
6
13
S(A)
S(B)
Fm ETU-01A
A transmit data rate clock for use by an
external data source.
External
Transmit
clock
7
14
B(A)
B(B)
To ETU-01A
A serial data rate clock input from the data
source.
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Table A-3 X.21 user data channel connector pin allocation