DCS

CDCSS or Digital Code Squelch (DCS) is a further development of the continuous tone-coded squelch system or CTCSS that uses a slow-speed, binary data stream passed as sub-audible data along with the transmission. Motorola calls this Digital Private Line or DPL. It consists of a 23-bit telegram sent repeatedly on the channel at 134 bits per second along with the voice transmission. This allows for over 100 possible fleet codes to be used. This gives it an advantage over the CTCSS tones in that there are more possible codes to use; however, it does use more bandwidth and can be affected by voice tones below 300 Hz if not properly filtered by the radio circuitry.

DCS Codes

Below is a chart of the DCS codes:

Inverted Codes

• The left column can be the standard, which makes the right inverted, or the left can be inverted which makes the right standard.

Thanks to Voyager for the chart values

Sound Card Decoding

ScanScope and DCS Decoder are free programs that can be used to decode DCS codes using a PC and receiver with discriminator output.

Related Links

More technical information on DCS can be found at these links:

• DPL / DCS Information
• DCS Explained
• CTCSS/DCS Technical Overview
• For the current ETSI Standard TS 103 236 Continuous Tone Controlled Signalling System (CTCSS) and Digitally Coded Squelch Signalling (DCSS) document click on the Standards tab on this page.

Related Wiki Articles

• Continuous Tone-Coded Squelch System
• Tone Signaling