I've been tasked to research automation options for telephony modem/gateway device testing with a group of DOCSIS voice engineers. For each new DOCSIS device with an eMTA that we receive we need to run dozens of tests on it. For example, pick up the phone, get a tone, dial a number and select an option.

To automate testing for the group I would like to have a script run each test in sequence. The script would run on a server behind the telephony modem/gateway, which would instruct the eMTA to make the calls.

I have researched Asterisk call files, which would run on the RasPBX I currently have set up. However, my concern with this solution is that the PBX originates the call and bypasses the MTA. The modem is merely used to pass the data originated by the PBX rather than register with our voice switch and route into the PSTN.

Essentially, I would like to turn a server into a basic wired phone. This server would send the tones down a phone line into the modem's RJ 11 port and then the embedded MTA would perform the call functions.

At this stage I am trying to ascertain whether or not this is feasible. Can a traditional wired phone be substituted with a server for this purpose?

  • I don't understand exactly what you're asking. It sounds like you're describing the basic functionality of a computer modem, just substituting a VOIP line over an eMTA for a physical phone line. It still plugs in exactly the same way. What's the issue you're having? – yoonix May 4 '18 at 17:47
  • The server should be able to perform DTMF. Essentially, can the server send dial tones down the USB-to-RJ11 cable to the eMTA? – zsh1337 May 7 '18 at 16:43

Yes, it is possible to use Asterisk call files for this type of general testing if you have a device attached to your Asterisk server with an FXO port.

FXO ports are typically RJ-11 connections intended to be connected to a POTS (Plain Old Telephone Service) line from a telephone company. In your case the eMTA is acting like the phone company.

Depending on what sort of tests you want to run, a modem could work. I.e. you could do basic dialing test. If you wanted to record and analyze audio, validate variations in callerid generation, test different forms of call supervision, etc, a dedicated telephony card will be much easier to use.

| improve this answer | |
  • Thank you for the response. I discussed this approach with the group and we agree to begin basic testing using DTMF encoding/decoding on the server. Implementing Asterisk may not be necessary as it seems this is possible using software that makes use of CCXML as indicated in this answer on Stack Overflow. – zsh1337 May 7 '18 at 16:09

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.