General EIA-422 Cable Information
This section applies to
Digi products equipped with EIA-422 asynchronous interfaces.
Physical Cable Characteristics
EIA-422 interface cables
should be shielded twisted-pair cables. Each signal requires two leads (one
twisted pair of wires) to
complete a balanced voltage digital circuit. The shield should be connected
to the Chassis Ground of
the devices at both ends of the interface cable.
EIA-422 Interface Signaling
The EIA-422 interface
provides four signals: Transmitted Data (TxD), Received Data (RxD),
Request To Send (RTS) and
Clear To Send (CTS). The functions of these signals are identical to
their EIA-232
counterparts.
EIA-422 Grounding Requirements
EIA-422 interface cables
must provide a ground path between the devices to be connected. This
ensures the integrity of
data transfers and control signals. This should be connected to the Chassis
Ground of each device.
Digi recommends using the cable shield for this purpose.
