User's Manual

54 MDS Master Station MDS 05-6399A01, Rev. D
5.6.5.1.4 AdvancedSettings
Soft-Carrier Dekey – Specifies how long (in ms) to wait after the removal of the keying signal before
actually dropping the transmitter’s carrier. The default setting is 0, but it may be set to any value up to
255 ms. In most cases, no change is required from the default setting. A possible exception is when the
transceiver is inter-working with certain early-generation MDS radio equipment.
Push to Talk Signal – Specifies the sensing polarity of the PTT line. This must be configured to one of
the following values:
Off – PTT line is not used.
Hi – The PTT line is active-high.
Lo – The PTT line is active-low.
Push To Talk Delay – Specifies a brief time delay after a keying event, which must expire before the
radio is allowed to transmit. The allowable range is 0 to 255 ms, with the default being 0.
Clear To Send Delay – Specifies a brief time delay between when an RTS (ready-to-send) signal is
received and when the CTS (clear-to-send) signal is returned. The allowable range is 0 to 255 ms, and the
default is 0.
Automatic Freq. Correction – Automatic Frequency Correction, is used to counteract the slight RF
frequency drift that may occur over time or through wide swings of ambient temperature. AFC should
only be enabled when operating this device as a remote, as all remotes in the system use AFC to track the
master station frequency. Under normal operation, the modem is capable of compensating for small
frequency errors even with this mode disabled. Enabling AFC further extends the frequency capture range
when operating with legacy hardware that may have significant frequency error.
Switched Carrier B Modems – In some networks, the Master unit is not keyed continuously (Ckeyed),
and transmits only when it has data to send to Remotes. This is known as Switched Carrier operation.
The Switched Carrier setting is only for use on radio modems with “B” suffixes (for compatibility with