Oricom DTX4000 Operating Instructions Manual page 21

Operations
Duplex
General
Your radio has a Repeater Access function to allow use of local repeater
station (if available in your area). Repeaters are shared radio systems
installed by interested parties (clubs, local business etc.) that pick
transmissions on specific channels and re-transmit (or repeat) the
received signal to another channel.
Repeater Station
The Repeater Access function can be set (from channel 1 to 8 and 41
- 48) used by local repeater stations. When activated, your radio will
receive the Repeater on its specific channel (all repeater outputs are on
channel 1 to 8 and 41 to 48) but transmit to the repeater channel 31
through 38 and 71 to 78.
(Factory default is set to On for all repeater channels).
e.g.
CH01 on Duplex mode will receive on CH01 but transmit on CH31.
CH02 on Duplex mode will receive on CH02 but transmit on CH32.
If you transmit on CH01 duplex mode, you are actually transmitting on
CH31.
The repeater station down converts your signal and retransmits on
CH01.
Your transceiver allows you to pre-select Duplex operation individually
on each channel.
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