My personal opinion on this is that DTMF tones cannot be sent out on the conferenced line. COnfirmed by the fact that the tones cannot be heard by the 2nd called party and but can be heard on the first which are two separate voice/CO paths.

The only explanation that I can think of why I was able to get thru on the second call
when I keyed the second extension number is perhaps:

1. the pbx system that I called on my first TEST call does not send an answer supervision while engaged in Autoattendant. Toshiba probably keeps DTMF enabled until the conferenced call is completed.

2. The second office trunk number I called may be set to provide answer supervision immediately to the calling party when it hits autoattendant.

If I can get hold of a prepaid card long distance platform that is setup not to provide answer supervision while keying in the pin numbers, I'll make another test call and let you know.

many many thanks again!
Danny