Since most folks are calling it T1/E1 rather than T-1/E-1, I am changing the doc to reflect this convention.
Gene Naden ----- Original Message ----- From: "Stephen R. Darragh" <[EMAIL PROTECTED]> To: "Discussions regarding The Asterisk Documentation Project" <[email protected]> Sent: Wednesday, August 17, 2005 10:01 PM Subject: Re: [Asterisk-doc] Connecting to a PRI > Final point - it's E1 and T1, not E-1 and T-1. Unless the dash is some > typographic mark for you. :) > > Gene Naden wrote: > > Thansks to all for your feedback. I have incorporated the following > > suggestions and corrections into this revised doc. Again, further criticism > > is welcome, it has been very helpful so far. > > > > 1. There is a discussion of E-1. It only lacks an example of the zaptel.conf > > file. The number of channels is 32 > > 2. ISDN PRI is a type of signaling used with E-1 and T-1. PRI is spelled > > out: "Primary Rate Interface." > > 3. "D" channels are "delta", not "data" > > 4. Correct spelling of "confiuration" > > 5. No longer says you cannot have PCI cards in a rack-mounted server > > 6. No longer says the cable is RJ45 > > 7. Zapata channels are one-indexed: Zap/1, Zap/2, etc. > > > > Gene Naden, MA > > Programmer Analyst > > GlobalTeldata II, LLC > > 4700 N. Ravenswood > > Chicago, IL 60640 > > (773) 878-3161 x 223 > > > > > > ------------------------------------------------------------------------ > > > > T-1, E-1 AND PRI > > In the context of Asterisk, T-1 and E-1 are digital telephony schemes > > that multiplex a number of voice channels onto one line. E-1 is used > > mainly in Europe and Asia, while T-1 is used in the United States and > > Canada. In either case, signaling and framing information must be > > carried, either within the voice channels or in separate, non-voice > > channels. There are various signallng and framing schemes. > > > > One signaling scheme that is used with Asterisk for T-1 connections > > is ISDN PRI (Integrated Services Digital Network, Primary > > Rate Interface.) With IDSN PRI, a T-1 connection has 24 channels. > > In the context of Asterisk, channels 1-23 carry voice and are referred > > to as "B" (bearer) channels. Channel 24 carries signaling information > > and is referred to as a "D" (delta) channel. > > > > ISDN PRI signaling is also used for E-1 connections. Such an E-1 > > connection has 32 channels. For Asterisk, channels 1-15 and 17-31 carry > > voice and are called "B" channels, while channel 16 carries signaling > > information and is called the "D" channel. Channel zero is used for > > framing. > > > > CONNECTING TO A PRI > > > > To connect to a PRI you use Zapata technology. Zapata is also used for > > connecting to POTS lines (ordinary, single channel analog phone lines) and > > analog phones. You configure Zapata for Asterisk in the file > > /etc/zaptel.conf. Therefore this file can have information about both > > PRI connections and POTS line connections. See the example below. > > > > You do not need a Channel Service Unit/Data Service Unit (CSU/DSU) to > > connect your PRI to the Asterisk computer. > > > > All the Digium cards for connecting to a PRI are PCI cards. The TE405P > > card is an example of a PRI interface card. It has four ports and therefore > > can connect to up to four PRIs. Alternatively, one or more ports could be > > connected to channel banks for analog phones. However, channel banks are > > beyond the scope of this discussion. > > > > Below is a sample Zapata configuration file (zaptel.conf). It shows the > > configuration for a single T-1 PRI, two analog phones and two POTS lines. > > > > # zaptel.conf > > > > loadzone = us > > > > #te405p card > > span=1,1,0,esf,b8zs > > bchan=1-23 > > dchan=24 > > fxols=1-23 > > > > #tdm400 card > > fxoks=97-98 > > fxsks=99-100 > > > > The 23 B channels and the D channel are shown. > > > > The line "fxols=1-23" reflects the fact that the connection is to a PRI > > rather than a channel bank. "ls" refers to "loop start." > > > > The way the channel numbering works is that the first 96 channels (one > > through 96) are for the TE405P card. The fxo and fxs channels, if any, > > must follow, rather than precede, the PRI channels. In other words, > > you cannot have fxoks=1-2, fxsks=3-4, bchan=5-27, dchan=28. If you > > do this you will get an obscure error message. > > > > Regarding the line beginning with the word "span", there is one span > > for each port that is in use. The "span" line has the following format: > > > > span=port number, timing, line build out, framing, coding > > > > The port number is one because the PRI is connected to the first port on > > the card. > > > > The timing should be 1 for one of the ports. The line connected to that > > port provides a timing reference. If other ports are used, the timing for > > those ports should be two or zero. Two means this line is a secondary > > timing reference and zero means this line is not used as a timing > > reference. > > > > Line build out reflects the length of last leg of the connection and is set > > to zero if the length is less than 133 feet. The specific values for line > > build out are specified in the sample zaptel.conf that comes with Asterisk. > > > > The framing option "esf" refers to "extended super frame" and "b8zs" refers > > to coding "Bipolar with 8 Zero Substitution." > > > > TROUBLE-SHOOTING > > When the PRI card was purchased from Digium, Digium has provided free > > technical support for configuring the card. > > > > The lights on the PRI card can be red, amber/green or green. When all is > > well they are green. > > > > If Asterisk aborts when you try to start it, there are several things you > > can check: > > > > The Linux modules for your Zapata cards have to be loaded in order for the > > connections to work. You load the PRI driver, wct4xxp, before you load the > > FXS/FXO driver, wctdm. > > > > You also have to execute the program ztcfg to get things to work. If all is > > well, when you run ztcfg it should not produce any output unless you > > specify verbose output ("ztcfg -vv"). When you run ztcfg, the lights should > > change to green, even if Asterisk has not been started. > > > > Loading of the modules may or may not be done automatically by the system. > > > > Digium says it is possible to construct a loop-back plug to test your > > PRI card. You do this using an RJ45 plug, connecting pin one to pin four > > and pin two to pin five. When the loop-back connector is connected to the > > card, the light should turn green. Again, the modules have to be loaded > > and possibly ztcfg has to have been run. > > > > The B channels listed in zaptel.conf must agree with the channels listed in > > /etc/asterisk/zapata.conf, otherwise Asterisk may abort when you try to > > start it. Zapata channels are indexed starting at one rather than zero > > (Zap/1, Zap/2, etc.) > > > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > Asterisk-Doc mailing list > > [email protected] > > http://lists.digium.com/mailman/listinfo/asterisk-doc > > -- > Stephen Darragh > Technical Director > Informed Technology > Ph: +61 8 9380 4244 Fax: +61 8 9380 4354 > _______________________________________________ > Asterisk-Doc mailing list > [email protected] > http://lists.digium.com/mailman/listinfo/asterisk-doc > _______________________________________________ Asterisk-Doc mailing list [email protected] http://lists.digium.com/mailman/listinfo/asterisk-doc
