Product specifications
Appendix A. I/F Modules 
75 
May 2011 
A.3 V.35 User Data Channel Connector 
When the ETU-01A is ordered with a V.35 interface, the physical interface is a 34-pin female M-
Block (Winchester) type connector wired in accordance with Table A-4. 
SIGNAL 
FUNCTION 
PIN CIRCUIT  DIRECTION DESCRIPTION 
Protective 
Ground 
A Frame ↔ 
Chassis ground. 
May be isolated from signal ground. 
Signal 
Ground 
B 
Signal 
Ground 
↔  Common signal ground. 
Transmitted 
Data 
P 
S 
TD(A) 
TD(B) 
To ETU-01A  Serial digital data from DTE. 
Received 
Data 
R 
T 
RD(A) 
RD(B) 
From ETU-
01A 
Serial digital data at the output of the ETU-01A 
receiver. 
Request to 
Sent 
C 
RTS 
To ETU-01A 
An ON signal to the ETU-01A when data 
transmission is desired. 
Clear to 
Sent 
D 
CTS 
From ETU-
01A 
Constantly ON. 
Data Set 
Ready 
E 
DSR 
From ETU-
01A 
Constantly ON, 
except during test loops. 
Data 
Terminal 
Ready 
H 
DTR 
To ETU-01A  Not used. 
Data Carrier 
Detect 
F DCD 
From ETU-
01A 
Constantly ON, except when a loss of the 
received carrier signal is detected. 
External 
Transmit 
clock 
U 
W 
ETC(A) 
ETC(B) 
To ETU-01A 
A transmitted data rate clock input from the 
data source. 
Transmit 
Clock 
Y 
AA 
TC(A) 
TC(B) 
From ETU-
01A 
A transmitted data rate clock for use by an 
external data source. 
Receive 
Clock 
V 
X 
RC(A) 
RC(B) 
From ETU-
01A 
A received data rate clock for use by an 
external data source. 
External 
Receive clock 
Z 
BB 
ERC(A) 
ERC(B) 
To ETU-01A 
A received serial data rate clock input from the 
DTE. 
Remote 
Loop back 
HH RL  To ETU-01A 
When on, commands ETU-01A into remote 
loop back, can disable by DIP sw. 
Local 
Loop back 
JJ LL To ETU-01A 
When on, commands ETU-01A into local loop 
back, can disable by DIP sw. 
Test Indicator  KK  TM 
From ETU-
01A 
ON during any test mode 
Table A-4 V.35 user data channel connector pin allocation 










