actually i have the same question... my motorola ht1250 USED to mute mdc-1200 all the time until recently when my city/county must have upgraded to the xts series radios. because the pl tone of 127.3 has a rather loud hummm in the background from the repeater but now you barely hear the hummmm at all and only like 5% of the time the mdc's get muted. its kinda frustrating because i love the dos mute option... my only answer for you is to go to the DOS tab under mdc and set the dos criteria type to "1200Hz OR 1800Hz"... if you set it to "1200Hz AND 1800Hz", theres an excellent chance you wont get it muted becuz it needs to know whats its going to do before it does it. otherwise i have mine all set to 0 om timers and everything i can think of... and DOS auto mute duration to 25, which i believe is the minimum setting... if its disabled it wont work... but like me, you might want to know what series of radios your city/county is using because here in grand island, ne... the HT series portables are not used anymore but in neighboring communities where they still use HT radios... it works... also, my cdm1250 mobile radio still mutes away like nothins changed... hope this helps ya!
