> What is available to connect two remote offices via T1?
Good question, actually, but one that opens up so many options! (It
gives us consultants a good living.)
Quote:> Ideally, I'd like to use a T1 on each end and provide:
> *) Intercom service,
What do the two offices have for telephone service now? If there are
PBXs, then tie lines via the T1 will do it. Even without a PBX, there
are ways to derive voice channels from a T1, to mate different types
of telephone system.
Quote:> *) TCP/IP traffic (Ethernet),
> *) (One/Several?) ISDN S/T or U lines. I'd like to be able to use
> ISDN phones on one end and on the other end connect to the
> Intercom system or to the LD Company via POTS or ISDN. Or to
> use, say, a Waverunner on one side and get thru the T1 to the
> main office, and then routed into the Ethernet on the other side.
> *) Anything else ISDN provides, like FAX.
> Do I need a PBX for all of this? Certainly some kind of switch-like
> routing seems necessary.
Several types of equipment terminate a T1. A few examples:
* A PBX. These typically handle 64 kbps data calls (period) too.
* A Data Service Unit. This takes all of the bandwidth and makes
it into one fat data channel. Fractional-T1 DSUs operate on a
subset of the 24 channels, as you specify.
* A channel bank. This is a static (configure by plugging in cards)
multiplexor. Option cards of all sorts are available. Each of
the 24 channels is picked up by one card or another.
* A nodal processor. This is like a fancy channel bank with software
configurability, multi-T1 networking, etc. Overkill for two sites
but worth it for larger networks.
* A drop-and-insert mux. This generally lets you pick off a couple of
data channels (n*64k) while feeding the remaining channels into a PBX,
Fractional-compatible Data Service Unit or whatever.
Quote:> How much traffic can fit on an S/T? For example, can I put all 24 B
> channels on the S/T bus concurrently without degradation or failure?
> (I doubt it)
The ISDN Basic Rate S/T bus handles exactly two B channels (one BRI).
T1 is a different animal.
One common way to go: Get a T1 to your long-distance company.
Designate some channels for access to their network ("WATS"-style
services.) Run others into a Fractional T1 for your site-to-site
needs (data, maybe some voice, etc.). They can deliver ISDN Primary
Rate using one D channel and however many B channels you designate
(the rest used for "FT1" or individual-channel services).
If you have an ISDN system at one end and want for some odd reason to
remote a Basic Rate channel, you can use a channel bank equipped with
Adtran's BR1TE cards. These take 3 channels and map 2B+D onto them.
They fit into standard D4-family banks so you can mix and match, or
use 8 to fill a T1. That's a common way to deliver "virtual ISDN".