JZ-RS4
2
Unitronics
RS232 Pinout
The pinout below shows the signals between the D-type adapter and RS232 port connector.
MJ10-22-CS25
D-type adapter
MJ20-RS
RS232 Port
RJ11
MJ20-PRG
– cable interface
Pin #
Description
Pin #
Description
Pin #1
6
DSR
1
DTR signal*
5
GND
⎯
2
GND
2
RXD
3
TXD
3
TXD
→
4
RXD
5
GND
⎯
5
GND
4
DTR
→
6
DSR signal*
*
Note that standard communication cables do not provide connection points for pins 1 & 6.
RS485 Settings
RS485 connector signals
A
Positive signal
B
Negative signal
Network Termination
1
OFF
1
2
ON
ON
2
ON
MJ20-RS comprises 2 switches.
ON
Termination ON
(Factory default setting)
OFF
Termination OFF
Note that you must move
both
switches in order to set the desired
state.
Network Structure
Termination =
ON
Termination =
OFF
Termination =
ON
B A
B A
B A
▪
Do not cross positive (A) and negative (B) signals. Positive terminals must be wired to positive, and negative terminals to negative.
▪
Minimize the stub (drop) length leading from each device to the bus. The stub should not exceed 5 centimeters. Ideally, the main cable should
be run in and out of the networked device.
▪
Use shielded twisted pair (STP) cables to network device, in compliance with EIA RS485.
