# Channel extension

This extension to the codeplug allows to set device specific channel settings for many TyT radios (and therefore also many Retevis radios). Not all settings are present in all radios. Unsupported settings are ignored during encoding or set to the default value during decoding.

## Example channel settings specifying the default values for TyT Retevis devices.

    tyt:
      autoScan: false
      emergencyAlarmConfirmed: false
      displayPTTId: true
      rxRefFrequency: Low
      txRefFrequency: Low
      tightSquelch: false
      compressedUDPHeader: false
      killTone: Off
      inCallCriterion: Always
      allowInterrupt: false
      dcdmLeader: false

## Common channel setting fields

autoScan

- If true, the auto-scan feature is enabled.

emergencyAlarmConfirmed

- Enables the confirmation of emergency calls. These fields are usually disabled as the radio will first establish the connection before the actual call can be started.

displayPTTId

- If true, the received analog PTT will be shown.

rxRefFrequency

rxRefFrequency

- Specifies some weird reference frequency setting for RX and TX. By default the value Low is used. Possible values are Low, Medium and High.

## Channel settings for TyT MD-390 and Retevis RT8

tightSquelch

- If set to true, the silent squelch is used.

compressedUDPHeader

- Some unknown flag. Usually disabled.

## Channel settings for TyT MD-UV390 and Retevis DM-2017

killTone

- Specifies the kill tone. Possible values are Off, Tone259_2Hz and Tone55_2Hz. Disabling or setting the kill tone to 259.2Hz or 55.2Hz, respectively.

inCallCriterion

- Specifies the in-call criterion. Possible values are Always, AdmitCriterion and TXInterrupt.

allowInterrupt

- Enables/disables interrupts if inCallCriterion is set to TXInterrupt.

dcdmLeader

- If DCDM is enabled, this flag specifies whether this radio is the channel leader. That is, if this radio provides the clock for the time-slots.

dmrSquelch

- Allows to set the squelch level for DMR channels. This prevents the LED to light all the time. The radio, however, remains silent irrespective of this setting.