QTech Data Systems QDR Digital 900MHz Radio - Manual (Page 8)

QDR – QTech Digital Radio – Owners Manual – v1.3 – August 2012 8
www.qtech.co.nz Tel: 03 3663713
Jumper Settings for Half Duplex RS485 (2-Wire)
Refer to Section 6 for further details on the jumpers
Jumper Position
JP3 In
JP4 Out
JP5 In
JP6 In
Pinout of RS485 Port when in Half Duplex Mode
QDR XL4 eXcel
Pin Pin Pin
Signal Input/Output Description
1 1 1 (NC) GND - Ground
2 2 3 B Input/Output Inverting Input/Output
3 3 2 A Input/Output Non inverting Input/Output
4 4 4 (NC) - - -
5 5 - - -
6 6 GND - Ground
Typical Half Duplex Connection
Note: Line termination resistors are inside the QDR
120 Ohm
A
B
120 Ohm
A
B