Pakscan IIE System Manual
86 of 132
Publication S177E V2.0 Issue 03/05
11.1.5 2-Wire and 4-wire RS485 communications
A 2-wire RS485 communications link consists of at least the following signals:
Data +
Data –
Signal ground
’Data’ and ’Data*’ are a balanced, bi-directional pair of signals which carry both transmitted and
received data. Note that the nomenclature used for the pair varies, ’+’ and ’-’ or ’A’ and ’B’ are
sometimes used. The PS410 also supports a control line, RTS.
A 4-wire RS485 communications link consists of:
Tx +
Tx –
Rx +
Rx –
Signal ground
Transmitted and received data have their own pairs of wires. The Pakscan IIE master station Port 1
supports 2-wire RS485 communications only.
