Zeadio 16 Key Dtmf Handheld Speaker Mic Microphone for Kenwood Car Radio Tm-261 Tm-271 Tm-461 Tm-471 Tk-7108 Tk-7150 Tk-7160 Tk-7180 Tk-7189 Tk-760 Tk-762 Tk-763 Etc. DTMF(Dual Tone Multi Frequency) function will open the radio's squelch only when it receives a DTMF code that matches one pre-programmed into your receiver. Each tranceiver is normally programmed with a unique code. The microphone has a heavy duty coiled cord with a 8 pin RJ connector The KMC-32 is a hand microphone, with DTMF function keys Mic clip hanger and 2 screws are included &lt;b&gt;Sold exclusively by Zeadio&lt;/b&gt;