Tones in general:
Note: The tone modes presented in the programmer for your radio are those that are available for use by your radio. The list shown here includes many tone modes found in many different radio models (not necessarily all in any one radio). These work the same way in all radios if they have the option.
- Tone - The value in CTCSS is transmitted to the repeater only. Any value that appears in Rx CTCSS (if that column is in the program for your radio) is NOT used.
- T SQL - The value in CTCSS is transmitted to the repeater and is used by the radio to block signals and noise on the frequency. If you make this selection incorrectly, you will hear nothing on this channel. If there is an RX CTCSS column in the programmer for your radio, this is the value used by the radio to block signals when TSql is engaged.
- DCS - The digital tone of the DCS column is transmitted to the repeater AND used by the radio to block incoming signals on this frequency. If the radio has a DCS and Rx DCS column, DCS is transmitted and Rx DCS is received by the radio. Else, with just a DCS column, that value is used for both transmit and receive.
- Rev CTCSS - Mutes the radio when a matching tone is received. This is just the opposite of TSql which blocks the signal until a matching tone is heard. This one blocks the signal with a matching tone.
- DCode - The digital tone of the DCS column is transmitted only to the repeater. There is no tone to block an incoming signal on the frequency. Any value that appears in the RX DCS column is NOT used by the radio when DCode is engaged.
- T-DCS - CTCSS Tone is engaged for transmission and DCS digital code is engaged for reception.
- D-Tone - DCS Digital code is engaged for transmission and CTCSS Tone is engaged for transmission.
Tones are funny things. You need a tone to get into most repeaters these days. So Tone (CTCSS) is usually a requirement.
Even if you are told that the repeater transmits a tone and you need to set up tone squelch, if you don't get things just right, you will hear NOTHING!!! It's better to leave Tone Mode as Tone and hear extra than to set it to TSQL incorrectly and lose all communications.