S-COM 6K Owner's Manual page 169

corresponding receiver path to TX1 determines when there is receiver activity
even if the corresponding path is not enabled.
If Receiver 2 is a link receiver, for example, the link can be "knocked down"
(disabled) after several minutes of link inactivity.
These receiver-driven macros should not be confused with the Repeater
Activity-Triggered Macro feature, which requires that Path 1 (Receiver 1 to
Transmitter 1) be enabled. See the Enable/Disable Path 1 (RX1 to TX1)
command.
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