This is very interesting guys! Here are the test results.

1. I made a test call to an office trunk office number. When the system attendant answered I Keyed in the extenstion number to get to the called party. Call was answered.

2. Made a conference call by pressing conference and dialed the same office trunk number. Upon hearing autoattendant I keyed in the extension number. CALL SUCCESSFULY WENT THRU!!! Which means that I was able to send DTMF tones.

We're not yet done!!!

3. BUT When I press the dtmf keys, the called party on the second connection doesn't hear any tones. The first party can hear it.

I tried this same test to another office trunk number(different company). The second time I make a call to another extension while the first call is on hold, the autoattendant cannot recognize my dtmf keys.