Dial Delay - NOT SIP Phone issue


This is a strange issue. I have 2 Asterisk boxes connected over IAX2 tunnel with GSM codec. when I dial any PSTN number, call waits for 20 to 30 seconds on Server#1 before it passes to Server#2. I have dialplan.xml for my cisco phones. all internal calls & inbound calls are fine.

Below what i see at CLI
– Executing [17323622138@internal:1] Set(“SIP/7438-b750fcb8”, “CALLERID(num)=7700”) in new stack
– Executing [17323622138@internal:2] Dial(“SIP/7438-b750fcb8”, “IAX2/newpbx:secret@”) in new stack
– Called newpbx:@
– Call accepted by (format gsm)
– Format for call is gsm
*** Delay starts here ***
*** Call connects only after 20 to 30 seconds delay ***

Please suggest…