[Asterisk-Users] why zap call transfer fails?

[Michael Jia]

Hi, 

I am configuring Asterisk with TDM400 card with 1 FXS and 1 FXO
module. My first goal is to allow phones to be able to call out
through the asterisk PBX.

After channels and dial plans setup, Zap/1 connect to phone and Zap/4
connect to provider , when I dial the phone, the following message
shows in the asterisk console

------------------
Starting simple switch on 'Zap/1-1'
    -- Executing Dial("Zap/1-1", "Zap/4/9999999") in new stack
    -- Called 4/9999999
    -- Zap/4-1 answered Zap/1-1
    -- Attempting native bridge of Zap/1-1 and Zap/4-1
    -- Hungup 'Zap/4-1'
-----------------
However, there is only 1 ringtone in my phone, and it becomes silent
and eventually the call was dropped.

But reversely, if i dial my home number from a different phone, i can
reach the PBX, and then by dialing an extension, i can ring the local
phone without any problem.

I only have problem dialing out. What could be the reason?

Thanks a lot.
Michael