[Asterisk-Users] FGD Support

[James Taylor]

For those of you who want to look like a "real" phone company, and plan on  
connecting to the LEC so that you look like a long distance carrier  
instead of a customer, there are some mods to the ZAP channel which must  
be made.

When you order Feature Group D as a "customer" Asterisk works fine right  
now.

If you order Feature Group D and want to provide service as a IC or IXC  
(long distance carrier) and provide Equal Access, you must "look" like an  
Equal Access End Office (EAEO).  To do this, there is an additional packet  
that must be exchanged and acknowledged in the dialing sequence.

I have submitted a request to Digium for a quote on this modification.

Jason Miller at interlinc.net has added his spport to this project,  
because he needs it working yesterday.

If you have an interest and would like to assist in getting this  
modification off the ground and completed quickly, then you might want to  
contribute financially.

If you have an interest and can't contribute, we'd still like to hear from  
you and know that this feature might help you.

Contact me off list if you can help.

James Taylor
MetroTel
3505 Summerihll Road
Suite 11
Texarkana, Texas  75503
903-793-1956

Below is a copy of my email to Digium:

This is a requst to modify the Zap channel to provide additional FGD  
support.

Please let me know what the charges will be, so we can get approval and   
get started.

As more and more Asterisk boxes connect to the PSTN, there is a need to  
look like an IXC or CLEC.
Short of SS7, MF signaling with FGD is the next best thing.

I'm woking with Jason Miller, who has sent in other support requests on  
getting FGD to work.

I've examined the source code and it appears that FGD works fine if you  
connect to a long distance carrier.

But, if you "are" the long distance carrier and connect via the LEC's  
Access Tandem, there's another packet that must be exchanged.  We've tried  
putting it in the dial command and can't get the timing to work since  
there are additonal winks.

Asterisk really looks like an Equal Access End Office at this point.

The exchange below illustrates overlap dialing, which is not generally  
going to happen with Asterisk.
Asterisk will have all customer digits and just fake the overlap.

Here's what takes place:

Customer -->  Asterisk -->  Access Tandem (LEC) --> IC (long distance  
carrier)

Origionating Sequence

Customer dials (10xxxx)+(0/1)+(NPA)+NXX
Asterisk				Access Tandem		IC

1. Seize ->
2. <-Wink
3. KP+OZZ+XXX+ST->
4.						Seize ->
5.						<- Wink
6. <-Wink
7. KP+II+ANI+ST or KP -ST ->
After customer completed dialing XXXX
8. KP+(0)+7/10D+ST ->
9.						<-Wink
10. <-Wink
11.						<-Answer Supervision
12. <-Answer Supervision


Terminating Sequence

IC					Access Tandem		Asterisk

			
1. Seize ->
2. <-Wink
3. KP+7 or 10D+ST ->
4. 					Seize ->
5. 					<-Wink
6.									Ringing->
7.									<-Answer
8.					<-Answer Supervision
9. <-Answer Supervision


Complete specs are in SR-TSV-002275.






-- 
James Taylor
MetroTel
3505 Summerihll Road
Suite 11
Texarkana, Texas  75503
903-793-1956