[Asterisk-Users] Asterisk behind external PBX +enable IVR

[Anand S. Katti]

Hello List,

	I have 3 questions. (I have TDM 11B)

1. My connection is like this

			PSTN
			|
			|
			SOME PBX
			/
		       /
		ASTERISK PBX
		|	\
		|        \
		SIP UA1   \
			SIP UA2


As you see, from aserisk box, if want to make outgoing calls, i have to
dial '0' and wait for the dialtone, and then dial the destination number.
for this to achieve i have following in extension.conf

	exten=> _0._,Dial,Zap/4/${EXTEN}

And this works.
But what is the better way to do this ?, like i want to dial 0 and wait
for the dialtone if dialtoneis received i will dial 8 or 10 digit
destination number. I want to have something like this....

	exten=> _0.NXXXXXXX,Zap/4/${EXTEN}; for 8 digit desti..no.
	exten=> _0.NXXXXXXXXXX,Zap/4/${EXTEN};FOR 10 DIGIT desti..no.
So what is the proper way to write the above  dialplan ?

Similarly, for some calls, i have to dial 9 and wait for dialtone from the
external PBX, and then dial the 4 digit destination number, but im not
able to write the dialplan for this.
Could someone shed light on this ?

2. How do i enable IVR on my asterisk machine ? I want to have extensions
like 1001 for SIPUA1 and 1002 for SIPUA2. So when a call comes from
outside then MY IVR should pick the phone and ask the caller to dial an
extension 1001 top talk to SIPUA1. When caller dials 1001, then the call
should be forwarded to SIPUA1.

Could someone tell how to do this methodiacaly...

3.I want to call from SIPUA1 to SIPUA2.

How the extension, or sip.conf gets modified for this ?

Thanks in advance for reading the mail till this end.
awaiting for the inputs.

Regards,
Anand