### 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

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