508 TMAA02-02 DTMF Microphone TM8100/TM8200 Service Manual© Tait Electronics Limited November 2007Installing theMicrophone Clip1. Install the microphone clip in the most convenient location for theradio user. It must be within easy reach of the user, but in such aposition that the microphone PTT key cannot be inadvertentlyactivated or jammed on.2. Connect the microphone clip to the negative supply if hookswitchoperation is required.20.2 AdjustmentRemove the DTMF microphone back cover and set the DTMF tone levelto approximately 60% deviation (±3kHz for wide bandwidth radios and±1.5kHz for narrow bandwidth radios).20.3 Radio ProgrammingThe following table shows the settings required for CH_GPIO1 in theProgrammable I/O form of the programming application. WhenCH_GPIO1 is set to Send Mic Audio To Spkr, then DTMF tones are fedinto the radio’s speaker at a reduced volume whenever a key on the DTMFmicrophone is pressed. This gives the radio user confidence that the tonesare being transmitted.Refer to the online help of the programming application for moreinformation.Figure 20.1 Correct DTMF microphone grommet seatingmicrophonegrommetcontrol headTable 20.1 DTMF microphone settings in the Programmable I/O form, Digital tabPin Direction Label Action Active Debounce Signal State Mirrored ToCH_GPIO1 Input None Send Mic AudioTo SpkrHigh None None None
