Inband DTMF during call setup

Hi all,
i’ve got an Asterisk 1.4.24.

here is my scenario:
phone (A) -> telco —> network —> ISDN -> gateway — iax2 ----> Asterisk (B)

my asterisk is connected in iax2 with a isdn/iax gateway
My phone (A) can only send in-band dtmf.

  • Is it possible to send in-band dtmf during call setup?
  • Is asterisk (B) capable to receive in-band dtmf during call setup (without answering)?

the read() cmd has an option “noanswer” that should do the trik.
i made some test and it seams to me that it works only if i put an answer() on top of my dialplan.

thank you very much.

You need to start by asking the telco, but it would be strange for a telco to permit bi-directional early media. I suggest it would be quite strange to allow early media even towards the caller, except if you were an official network operator.

I don’t know if Asterisk can handle inbound early media, but the telco is much more likely to the the unsurmountable problem.