[Asterisk-Users] Some questions regarding T1's

[Colin Anderson]

>Exactly 72 employees each with a direct telephone number that goes
>directly to their phone.  Ex: Bob is 444-555-6666 and Lisa is 444-555-6667.
>Let's say they don't have a PBX yet.
Easy as pie with a PRI/T1. Typically the telco assigns a DID (Direct Inward
Dial) number to the PRI and Asterisk parses the last 4 digits of the DID to
assign it to an extension in the incoming context. So for a number that is
555-1212, Asterisk will expect a statement like this in the incoming
context:
Exten => 1212,1,Dial(somewhere internal)
This extension number is only valid for the incoming context so of course
you can have an external "extension" that corresponds with the DID and an
internal extension number that the user can dial other phones with. They are
mutually exclusive. 

> Statistically, the max number of outside lines ever busy at the same time
>was 24 (how conveniently T1-like).  They don't want to change their
business
>cards, so 444-555-6666 should still reach Bob, but now by going to the PBX
>first.  The PBX should recognize that the call was made to 444-555-6666 and
>switch it to Bob automatically.  Bob should see the Caller ID of the caller
>on his phone.
Yup see above. You need to assign all of the existing numbers as DID's on
the PRI. 

>Asterisk PBX - yes

>A Digium T1 line for a connection to the phone service provider - actually
a Digium or compatible PRI/T1 *card*
>A T1 line from Bell Canada (or other) - yes
>Something (not sure what) on the outside to connect to those 72 phones (3
>T1 cards internally connecting to a wire panel, in turn connected to 60
>phones?
If you are using IP phones then you leverage your existing Ethernet
infrastructure. If it is 72 regular, analog phones then you need an FXS
Channel Bank. Google for it. Try to convince them to use IP phones, they
rock.
>Is this it?  Do I need anything else?
Experience and patience. And a backup to help you out if you are stuck like
a consultant on -biz
>Is is possible to have 72 numbers associated to a single T1 (more numbers
>than lines)?
Yes, up to 10K per PRI assuming 4 digits are passed by the PRI, sometimes
you can get 7, ask your telco
Will Asterisk be able to recognize (and how?) which number the call came
on, so it can run the right dial plan?
Yes, see above
This migth be a Canada-specific answer, but I'll try:  When leasing a T1
line, does the regional code  have to be based on geohraphy?  Could I have a
T1 with 416 (Toronto) numbers located in Montreal (514)?
Talk to your telco. They can probably do it but you will most likely have to
eat the long distance.
hth