I must not be explaining my question clearly. Is E&M a framing protocol that the signal that travels "through" the T1's channels conforms to, or is it a wire protocol that will drive a pair on the centronics connector. If it is the former case, then what drives the pair on the centronics connector, and will i be able to plug a standard analog phone into it (and expect it to work)? If it is the latter, then I assume that there is no easy way to connect an analog phone.
Thanks to everyone for responding to my questions. --- Ilia Mirkin [EMAIL PROTECTED] On Mon, 2004-09-06 at 11:33, Chris A. Icide wrote: > Ilia, > > Think of a channel bank as a concentrator. In a single T1 channel bank, > you concentrate 24 analog two wire phone connections into a single 4 wire > digital interface. > > So in your case, the RJ45 connector is for the T1 interface to Asterisk, > the local CLEC, or whatever you intend to connect it to. On the T1 side, > there has to be several layers of signalling and encoding. Alot of this > information is superfluous, but may help you when it comes to understanding > your configs. > > Before we even talk about E&M signalling, you have the T1 framing and > encoding. This is used to allow both ends of the T1 circuit to understand > how the 24 channels are being configured on the 4 wire circuit. It's > generally going to be either sf, d4 or esf, b8zs. This is known as the > framing and encoding. > > Once those are agreed upon, then we need to set up the way the T1 is going > to signal across the channels. Normal phone lines (analog) use voltages, > resistances, and dtmf to signal what it is doing. Since a T1 is a digital > circuit we can't do that, so we need to set up another way to signal, so > that the channel bank knows what to do when we send some kind of digital > signal. In this case, this is the E&M signalling you asked about. > > Finally, you probably are looking for some way to plug your phone's RJ11 > connecter into the channel bank. Unfortunately it's not that easy. That > big Centronics style connecter is where you actually have to plug up the > phone. there are 24 pairs of contacts in that connecter that are > associated with each channel on the T1 circuit. Historically, you would > connect up a cable of 50 conductors connected to the centronics connector > on one end, and then to one side a punch down block on the other (just a > quick-connect style access device for copper wire). On the other side of > the punch down block, you would connect the wires that would then run to > the remote wall jacks, etc. where your phones plug in. > > The problem you have is wither by google mastery or just plain brute force > testing, you need to figure out the pinout of that centronics port before > you can connect up any phones successfully. > > -Chris > > On 10:56 PM 9/5/2004, Ilia Mirkin wrote: > >While I understand everything that you have said, I'm still a little > >confused. Yes - I have what looks like a centronics connector on the > >back. So, I can do "t100p with e&m signalling" <-> "act-1241 e&m card" > ><-> what? Namely, if the E&M card deals with the T1 end of the channel, > >how do I get that to a real phone? Will it "just work" if I plug an > >analog phone onto the correct pair coming out of the connector in the > >back? If not, what is the output of the E&M card? (and, more > >importantly, what would I need to do to hook it up to an analog phone?) > > > >Thanks for clearing things up. > > > >--- > >Ilia Mirkin > >[EMAIL PROTECTED] > > > >On Sun, 2004-09-05 at 04:31, Steven Critchfield wrote: > >> On Sun, 2004-09-05 at 03:10, Ilia Mirkin wrote: > >> > hi, > >> > > >> > i have some newbie questions about channel banks. i have an adtran > >> > act-1241 sitting around. it accepts D4 modules, and it contains a number > >> > of e&m cards. > >> > > >> > first of all, how does this thing work? a t1 contains 24 channels, and i > >> > noticed that the channel bank has space for 24 cards. what do these > >> > cards do? what are their outputs? the ones that are in there have some > >> > outputs on the front marked "test", but nothing else. there are a number > >> > of wires coming out the back (48, if i had to guess), and it has a few > >> > ports on the front which seem to be able to take in a T1. am i correct > >> > in understanding that it is the card in the bank that determines the > >> > signalling style, and not the t1? as such, is there no way that i could > >> > use it in its current configuration to have it talk with analog phones > >> > (i.e. something like t100p -> act-1241 with e&m cards -> phone)? i'm a > >> > bit unclear on the different signalling types, and their > >> > intercompatibilities. > >> > > >> > if anyone could shed any light into this, i would very much appreciate > >> > it. > >> > >> Think of the T1 as 24 digital digital pathways. The coding of each > >> pathway must be compatible on each end. With E&M cards, you signal with > >> E&M and the line will work. The cards plug into a backplane where the > >> controller routes the digital signal to the card and then optionally > >> hook up the output from the card to a connector that consolidates many > >> lines. Look for something that looks like an older 50 pin scsi D > >> connector. > >> > >> If there is 2 RJ45 jacks on the front, and 2 50 pin D connectors on the > >> back, then it is likely that each card controlls 2 lines each. If there > >> is only 1 50 pin connector, then there is only 24 channels. > >> > >> Hope that helps. > > > >_______________________________________________ > >Asterisk-Users mailing list > >[EMAIL PROTECTED] > >http://lists.digium.com/mailman/listinfo/asterisk-users > >To UNSUBSCRIBE or update options visit: > > http://lists.digium.com/mailman/listinfo/asterisk-users > > _______________________________________________ > Asterisk-Users mailing list > [EMAIL PROTECTED] > http://lists.digium.com/mailman/listinfo/asterisk-users > To UNSUBSCRIBE or update options visit: > http://lists.digium.com/mailman/listinfo/asterisk-users _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
