Here are some troubleshooting hints for the Radio Interface:

Audio distortion and white noise are by far the most common reason for DTMF Command Sequence failures on the Text Message Gateway!

Set the receiving radio squelch as tight as possible. Inter-modulation (intermod) and random interference that breaks the receivers squelch threshold can trick the program into believing that a valid DTMF Command Sequence has been received. It can also trick the program into sending group pages or changing the System Mode that are not intentional (this condition is identified by having no traffic on the receive frequency, but a page gets magically initiated). Consider changing the receiver location in order to reduce interference and intermod, or modify the antenna system to reduce intermod (via a narrow band pass filter) or be more directional (a dedicated yagi or corner reflector).

Set the receiving radio audio level to the lowest setting that produces reliable results. Excessive receiver audio levels introduce distortion that can trick the program into believing that a valid DTMF Command Sequence has been received. It can also trick the program into sending group pages or changing the System Mode that are not intentional (this condition is identified by having traffic on the receive frequency, and a page gets magically initiated by the tones of someone's voice)

Use the Diagnose Audio screen (Setup | System Setup | Diagnose Audio button) to adjust the computer's Record Line In control in conjunction with the radio's audio output to produce sharp (no flat topping) signals on the waveform (top) display that peaks between 50 and 100 %. This will ensure that you are working with a clean signal that is not distorting and is well within the program's ability to recognize only valid DTMF codes.

Try adjusting the (Setup | System Setup) Audio Format setting for a more reliable DTMF decode rate. If the receiver has DSP (Digital Speech Processing), set the number of bits equal and try setting the rate (Kbits/sec) to a multiple, or match, or double (ideal) that of the receiver.

Audio modes usually differ from the radio (usually Mono) to the computer (almost always Stereo). Select the cable (Mono-to-Stereo or Stereo [always use shielded cables for this purpose!]) accordingly. Use the Diagnose Audio screen (Setup | System Setup | Diagnose Audio button) along with all the (Setup | System Setup) Audio Channel settings to determine which channels you have audio present on. Always select the Audio Channel setting that is appropriate for the channels where audio is present.