Specifications

V.24, V.35 and X.21 Interface Connectors A-1
Appendix A
Connector Wiring
A.1 V.24, V.35 and X.21 Interface Connectors
Table A-1 describes the signal assignments for the FOM-40 V.24, V.35 and X.21
DTE interface connectors.
Table A-1. DTE Interface Signal Assignments
V.24 V.35 X.21 Description Signal
Function
DB-25
Standalone
and Card
Cage
DB-25
Card
Cage
34-Pin
Standalone
Pin Circuit
DB-25
Card
Cage
DB-15
Standalone
Pin Circuit
(Function)
Protective
Ground
1 1 A Frame 101 1 1 ----
(Shield)
Chassis Ground. It may be
isolated from Signal
Ground.
Signal
Ground
7 7 B Signal 102
GND
7 8 ----
(GND)
Common signal and DC
power supply ground.
Transmitted
Data
2 9
11
P TD(A) 103
S TD(B) 103
2
14
2 T(A)
9 T(B)
(Transmit)
Serial digital data from
DTE. In sync applications,
the data translations must
occur on the rising edge of
the transmit clock.
Received
Data
3 12
13
R RD(A) 104
T RD(B) 104
3
16
4 R(A)
11 R(B)
(Receive)
Serial output from the
modem receiver. In sync
applications, the data
translations occur on the
rising edge of the clock.
Request to
Send
4 4 C RTS 105 4
19
3 C(A)
10 C(B)
(Control)
A positive level to FOM-40
when data transmission is
desired.
Clear to Send 5 5 D CTS 106 A positive level from
FOM-40 with delay, after
receipt of Request to Send,
and when FOM-40 is
ready to transmit.