Specifications

Table Of Contents
Chapter 6 EIA-422 asynchronous interface 29
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.
Interface signaling
The EIA-422 interface provides four signals:
Transmitted Data (TxD)
Received Data (RxD)
Request To Send (RTS)
Clear To Send (CTS).
The functions of these signals are identical to their EIA-232 counterparts.
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.
Chapter 5
EIA-422 asynchronous interface