[Asterisk-Users] Ideal setup for PRI/T1 and TE110P

[Robert Woodcock]

On Tuesday, April 04, 2006, JT Zemp wrote:
> I'm setting up a T1 and my telco has a bunch of questions it wants me to
> answer. I know much of the TE110p is configurable to do any of this, but
> I wanted to know if there is an optimal or preferred setup.
> 
> Any help would be appreciated. Here is the quiz my telco is giving me:
> 
> Wiring: 4-Wire | Coax | Fiber (I'm assuming 4-wire is the correct interface)
> Jack type: RJ45 | 48? (I'm pretty sure the TE110p is RJ45 - correct?)
> Dial Tone: None | Yes-Precise | Yes-SCC
> Framing: SF | ESF (I'm assuming ESF)
> Line Coding: AMI | B8ZS
> Signaling Start: Ground Start | E&M | Loop Start w/ring | Loop Start w/o
> ring (which of these does kewlstart deal with?)
> Pulse Mode: DTMF | MF (I assume DTMF)
> Outpulse Mode: Wink | Immediate | Seizure (If Seizure, then Origination
> or Digit Collection)
> Will ANI delivery be required for Toll-Free service? (I'm assuming Yes
> if we want to pass our caller id?)

ESF framing and B8ZS line coding are standard in the US, and the TE110P is
a 4-wire interface. I'm not aware of any real practical difference between
RJ45 and RJ48, although some RJ48 jacks have extra shielding and can
automatically go into loopback when you unplug a cable from them.

Specifically the signalling, dial tone, Pulse Mode, Outpulse Mode, and ANI
questions lead me to believe that you aren't getting a PRI T1 line.

The differences between PRI and non-PRI are that PRI uses ISDN digital
signalling instead of analog signalling. Which in turn means that:

* One channel gets eaten for digital signalling (this channel gets called a
  D channel, the voice channels are B channels). So a 24-channel T1 becomes
  a 23 B channel + 1 D channel T1.

* Telcos typically charge slightly more for PRI.

* Call setup is instantaneous. With non-PRI, you're sending digits via DTMF
  and each one takes a few hundred milliseconds. Typically only ANI (calling
  billing number) and/or DNIS (called number) digits are sent, and you won't
  get extra fields like CallerID (often the same as ANI, but often not) at
  all. Often your telco will not send you this ANI information unless you
  specifically request it because it makes incoming calls take too long.
  You also won't be able to send outgoing callerID information to your telco
  at all.

You'll be a lot happier going with PRI.