Instruction manual

ACU-1000 Operations Manual
2-28 Interoperability Now
QA5 Ping-Pong Problems?
Some radios have a tendency to unsquelch momentarily at the end of each transmission. In an
ACU system, when two radios are cross-connected, whenever one radio is unsquelched, the
other is keyed. If a cross-connected radio exhibits the momentary unsquelch after TX behavior,
the cross-connected radio will inappropriately transmit. If both radios unsquelch at the end of
each transmission, the system will “ping-pong”, with first one radio keyed momentarily and
then the other. This effect can be experienced with the DSP module set to either the COR or
VOX Squelch Types.
To ensure that a radio being interfaced will not create a “ping-pong” behavior, key the radio
and check for signs of a momentary unsquelch at the end of the transmission. This can be done
by cross-connecting the HSP module with the radio. Key the HSP handset and see if the HSP’s
PTT LED comes on momentarily after the transmission is ended. If the PTT LED comes on,
the ACU should be set to ignore this inappropriate COR signal by enabling the COR Inhibit
after PTT feature.
NOTE: While the COR Inhibit Timer will prevent ping-pong and
inappropriate keying of cross-connected radios; it will also prevent the
radio from receiving a legitimate signal until the timer expires. This is not
usually a problem because the radio is normally producing a burst of
noise during this time. If system performance with the COR Inhibit Timer
enabled is unsatisfactory, switch to VMR mode.
See “(QA3 Yes) Set Squelch Type to VMR Mode”.
(QA5 Yes) Adjust COR Inhibit Timer
• The default setting for the COR Inhibit Time after PTT is 100 ms... If this does not
prevent the DSP front panel COR indicator from lighting momentarily at the end of a
transmission, set to the next highest time and repeat the test. (Note: The Signal LED
may still light.)
• Note: The Signal LED may still light.
• Continue to raise the time setting one step higher than the time required to prevent the
inappropriate COR indication.
• It may be necessary to check system performance with two radios cross-connected
(rather than using the HSP) to ensure the optimum COR Inhibit Timer Setting.
• Click “Apply” to save the setting.
(QA5 No) Jump to QA6