Yaesu FT-8800R Operating Manual

Also see for FT-8800R: Operating manual Brochure & specs Operating manual Technical supplement Operating manual

Contents

TONE CODED SQUELCHYaesu FT-8800R Operating Manual (courtesy of W5JCK) Page 34 of 83DCS Code InversionThe DCS system was first introduced in the commercial LMR (Land Mobile Radio) service,where it is now in widespread use. DCS is sometime referred to by its different proprietarynames, such as DPL® (Digital Private Line®, a registered trademark of Motorola, Inc.).DCS uses a codeword consisting of a 23-bit frame, transmitted (subaudible) at a data rate of134.4 bps (bit/sec). Occasionally, signal inversion can result in the complement of a code tobe sent or received. This prevents the receiver squelch from opening with DCS enabled, as thedecoded bit sequence would not match that selected for the operation.Typical situations that might cause inversion to occur are: connection of an external receiverpreamplifier, operating through a repeater, and connection of an external linear amplifier.Note that code inversion does not mean that any of the above listed equipment is defective.In certain amplifier configurations, the output signal (phase) is inverted from the input. Smallsignal or power amplifiers having an odd number (1, 3, 5, etc.) of amplification stages mayresult in inversion of a transmitted or received DCS code.While under most circumstances this should not occur (amplifier designs and industrystandards take this into account), if you find that your receiver squelch does not open whenboth you and the other station are using a common DCS code, you or the other station (but notboth) can try the following:1. Press the SET key momentarily to enter the Set mode.2. Rotate the DIAL knob to select Menu #11 DCS.N/R.3. Press the DIAL knob momentarily, then rotate the DIAL knob to select themode:• TRX N : Encoder; Normal, Decoder; Normal• RX R : Encoder; Normal, Decoder; Reverse (Inverted)• TX R : Encoder; Reverse (Inverted), Decoder; Normal• TRX R : Encoder; Reverse (Inverted), Decoder; Reverse (Inverted)4. Press and hold in the DIAL knob for ½ second to save the new setting and exitto normal operation. 0. Remember to restore the default setting to TRX N (Encoder; Normal,Decoder; Normal) when done.