APX8500 DTMF

[stevetucker]

Hi, does anyone know if its possible to program an APX8500 to send DTMF tones in ASTRO25 mode ?

The application is for making phone calls over a suitable telephone interconnect.

Thanks

[Karl NVW]

The P25 vocoder feeding audio to the telephone interconnect should have its software version upgraded to match the APX8500, to ensure there is no frequency translation of the DTMF tones.

[labontef]

Did you find the answer to your question?
Really interested to know that as well

[ASTROMODAT]

I believe the P25 protocol standard requires a subscriber sets’ DTMF transmissions in the P25 digital mode to encode analog DTMF into unacknowkedged Data 18 (or Data 12?) didital bits. In turn, to convert the data bits back into analog DTMF tones, this operation is done in the DIU3000, and the DTMF tones are subsequently fed into the MRTI autopatch unit that is attached to the huge multi pin port on the rear if the DIU3000, and finally injected into the telephone line. I have this setup, and it works great for running autopatches in the P25 mode, as the DIU3000 serves as the D/A and A/D converter interface between the digital P25 and analog modes. I have no idea as to how to accomplish making P25 autopatch calls with the PSTN without the use of the DIU3000, albeit I would guess it can be done, such as with the typical multi million $ trunked P25 system. I’m addressing P25 autopatch mode via a small P25 conventional system.