V.35 Synchronous Cable Wiring - DB-25 Connectors

V.35 wiring allows concentrators to be installed in remote locations and connected to the host adapter via V.35 DSUs/CSUs, frame relay adapters, fractional T1s or ISDN terminal adapters.

Host Adapter to Local V.35 Device

C/X or EPC/X
Host Adapter
(HD-15 Male)
 
Local
V.35 Device
(DB-25 Male)
Signal
Pin
Pin
Signal
RxD-
1
Connected to
3
RxD-A
RxD+
2
Connected to
16
RxD-B
RxC-
4
Connected to
17
SCR-A
RxC+
5
Connected to
9
SCR-B
TxD-
6
Connected to
2
TxD-A
TxD+
7
Connected to
14
TxD-B
TxC-
9
Connected to
15
SCT-A
TxC+
10
Connected to
12
SCT-B
GND
12
Connected (via shield) to
7
GND

Jumpered at V.35 End
4, 5
RTS, CTS

Modem to Concentrator

Remote
V.35 Device
(DB-25 Male)
 
Concentrator
"Host Adapter" Port
(HD-15 Female)
Signal
Pin
Pin
Signal
RxD-A
3
Connected to
6
RxD-
RxD-B
16
Connected to
7
RxD+
SCR-A
17
Connected to
9
RxC-
SCR-B
9
Connected to
10
RxC+
TxD-A
2
Connected to
1
TxD-
TxD-B
14
Connected to
2
TxD+
SCT-A
15
Connected to
4
TxC-
SCT-B
12
Connected to
5
TxC+
GND
7
Connected (via shield) to
12
GND
RTS, CTS
4, 5

Jumpered at V.35 End