12
Raveon Technologies Corp.
Pin #
Name
Direction
Function
Level / Specification
1
Do not connect this pin to anything.
2
B
I/O
B(+)
Non-inverting RS-485 data line
3
A
I/O
A(-)
Inverting RS-485 data in line
4
Do not connect this pin to anything.
5
Do not connect this pin to anything.
6
GND
-
Ground
Connect to earth ground.
The RS-485 differential line consists of two pins, A and B.
B
TxD+/RxD+ aka non-inverting pin which is positive (compared to A) when the line
is idle.
A
TxD-/RxD- inverting pin which is negative (compared to B) when the line is idle.
Configuring
The radio will auto-detect the 485 Tech Series board and set all necessary parameters
to enable RS485 communication.
The radio will only support RS485 Simplex. In simplex RS-485 mode, the
radio’s
serial
data receiver is internally disabled whenever it sends a character out the serial port, so
that it will not receive its own data.
If you wish to run the RS-485 in full-duplex mode using two radios, the interface must
be wired with two separate pairs of wires; A&B on one pair, and Out+ & Out- on the
other pair.
The radio
’s RS-485 I/O circuit uses 3.3V logic to drive the lines, and the RS-485 pins
are ESD protected to ±15kV and 7kV human body model
.
Input current is less than
150uA. Output current when not driving the line is less than 50uA.
Simplex or Full Duplex
Simplex is the default. In simplex RS-485 mode, the serial data receiver is internally
disabled whenever it sends a character out the serial port, so that it will not receive its
own data nor will it receive data from any other device when it is sending data out.
If you want to use RS-485 full duplex with tri-state outs, utilize the RS-422 version of
the Tech Series panel, and use it in your system. RS-422 4-wire tri-state operates the
same as RS-485
4-Wire Tri-State Simplex.
