Section 3. Operation
3-8
CONSIDERATIONS WHEN USING DIGITAL CODED SQUELCH (DCS)
When a DCS radio unkeys, it sends a 134.4 Hz squelch tail elimination turn off code bit
sequence for about 120 milliseconds. To avoid potential problems, users should not be
installed on the adjacent CTCSS frequencies of 131.8 and 136.5 if possible.
When installing DCS codes for the first time, use this procedure:
1. Use a radio with a known digital code.
2. Use the DCS encode test mode in the Model 38 to generate the digital squelch code that
the mobile is set to. If the mobile does not unsquelch, use the Model 38 digital encode
invert selection. The mobile should unsquelch on either the normal or inverted code.
3. Set the transmitter CTCSS/DCS encode deviation using a CTCSS tone, not a DCS code.
Most deviation meters will give an inaccurate reading of DCS deviation.
4. Make sure Jumper JP3 is in the “B” position (factory default).
5. To setup a DCS user in the Model 38 database, select a user number above the last
CTCSS tone (38 or 50). Enable the user and set the DCS decode number. Key up the
mobile and verify that the Model 38 “decode” led follows the transmission. If the mobile
is not decoded, try inverting the Model 38 receive polarity.
6. Once a single mobile is working through the Model 38, additional mobiles may be added.