Former user7 years ago000Can a Tritel Elm2 telephone (with RJ11 adapter and set to frequency dialling (FO)) be used with it?Show in original language (German)Former employee7 years ago+110 Helpful answerHello Cisco reports that this device is compatible with all industry standards. If it does not work, you can return it. GreetingsShow in original language (German)Commentmathiasger07 years ago+110An old Tritel telephone basically works, but sometimes the old devices have trouble ringing because the power of the ATA devices is missing compared to an old central unit.Show in original language (German)Comment2 comments