What do you use for your incoming line?
> ports. I am thinking about going T1 not only to keep up with the
> "Possible" technology of 56k since it only works if there is one
> conversion in the line.
This is true- but I wouldn't let the possibility of 56K 'fake digital'
modems affect the decision to change how your lines come in.
> What is the difference between channelized t1 and regular T1.
>
> Which is better?
Physically they are all the same. Logically they are all 24 channels
of 64000 bits each.
There are three different common ways of provisioning service over a T1,
in increasing order of (usual) price they are:
1. leased line 'clear channel' data.
This is the usual 1.5Mbps line between internet sites.
2. Channelized T1
This provides 24 channels of 56K digitized audio (the
missing 8K is used for signalling). This is what USR
'Total Control' racks and some PBX systems use.
3. Primary Rate ISDN
This is 23 'B' channels of 64K data, with the 24th channel
being the 'D' channel signalling. Each channel can be used
for pure data or digitized audio from analog calls.
> Does the PM3 support both?
I believe currently incoming calls are only accepted with PRI, but
channelized T1 is in the works.
> What is a rough estimate of a a T1 with 24 dialin numbers from
> bellsouth? Channelized or not whichever apply?
You need at least channelized to accept calls from your users.
I've done ISDN consulting around the Midwest, but it's been mostly in
Ameritech's service area, where you're looking at some really hefty
rates.
Take a look at Dan Kegel's ISDN page for links to price and hardware info:
http://alumni.caltech.edu/~dank/isdn/
> Can either T1 do ISDN? So the customer calls one phone number and gets
> either ISDN or Analog when dialing in?
Of the three, only PRI can do ISDN. It also can do analog.
Channelized can do analog only.
Either should be able to do new '56K' fake-digital modems.
> Does the PM3 do ISDN on the 24 channels without any modem cards. In
> other words the modem card are only if you are going to support analog
> calls.
Yes.
> conecerning the PM3 Do you have to provision the t1 so that lets say 8
> are for analog and 16 are for ISDN, so if 8 analog users are on and
> another call will it get a ninth channel that is not used or do you have
> to specify which are anolog and which are digital.
PRI gives 23 channels...
The PM-3 itself does not require that you pick- it might not even be possible?
Some telcos do require that you specify which DNs are analog and which
digital in order to set up hunt groups.
If you install 8 modems, then from one PRI you can have up to 23 total
calls, if all 8 modems are in use, then 9th modem caller will be blocked.
> I would appreciate a little light on the subject.