Instruction manual

Setup and Installation
38 025-9209
Radio Connection
The Radio Connector P3 on the RTU requires a minimum of six connections to interface
with the radio. The shaded rows in Table 19 indicate that those connections are optional.
Table 19. RTU Radio Connector (P3) Pinout
Pin # Connection Schematic Label
1 Power +12V
dc
2Ground GND
3 Push to Talk PTT OUT
4 Push to Talk Common PTT COM
5 N/A
6 Carrier Detect COR
7 Ground GND
8 Transmit Request
iii
TXREQ
9 Transmit Audio TXAUD
10 Receive Audio RXAUD
Step 1. Cable Connection
You should find a small clear plastic bag containing a plastic 10-pin connector and 10 metal
crimp pins. This connector mates with the Radio Connector P3 on the RTU. Construct a
cable using this connector to provide an interface to the radio that provides the six
connections listed above.
Step 2. Carrier Detect and Push to Talk Settings
Verify correct jumper settings for Carrier Detect and Push To Talk (PTT) based on the radio
you are using.
Carrier Detect
JP1
A = 10 kΩ pull-down to ground on Carrier Detect input
B = 10 kΩ pull-up to +12 V
dc
on Carrier Detect input
If your radio provides a logic change of 0-5 V
dc
when channel is busy, install JP1 in the A
position and set the Carrier detect level as high in the RTU.
iii
Transmit Request — This line will allow up to 15 RTUs to connect to a single Radio Transceiver. Transmit
Request prevents multiple units from transmitting simultaneously. To use, just connect a single wire to this pin
between all the RTUs on the same Radio Transceiver. The RTU with the lowest ID will have priority in using
the Radio.