### Eight-Wire Direct Concentrator Wiring

Host Adapter or Concentrator "Remote" Port (HD-15 Male) |  | Concentrator "Host Adapter" Port (HD-15 Female)
--- | --- | ---
Signal | Pin | Pin | Signal
RxD- | 1 | Connected to | 1 | TxD-
RxD+ | 2 | Connected to | 2 | TxD+
RxC- | 4 | Connected to | 4 | TxC-
RxC+ | 5 | Connected to | 5 | TxC+
TxD- | 6 | Connected to | 6 | RxD-
TxD+ | 7 | Connected to | 7 | RxD+
TxC- | 9 | Connected to | 9 | RxC-
TxC+ | 10 | Connected to | 10 | RxC+
GND | 12 | Connected (via shield) to | 12 | GND

The synchronous cables provided by Digi with the concentrators are Eight-Wire Direct (EIA-422) cables. This is the standard method for connecting concentrators to Host Adapter synchronous lines, and to other concentrators.

Eight-Wire Direct cables provide transmit and receive data signals plus discrete clock signals for transmit and receive data. This permits synchronous data rates of up to 10 megabaud, which results in the maximum data throughput under moderate to heavy loads.

The Eight-Wire Direct cable is a twisted pair cable with a male HD-15 (high-density DB-15) connector at one end and a female HD-15 at the other end. The cable should be shielded, and the shield must be connected to the HD-15 connector shell at both ends.

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