I think the main thing to note about cT1s is bit robbed signalling i.e channel asscociated signalling normally used to transport voice. Therefore, we've got 7 bits of payload, 1 bit for signalling for every timeslot and 1 bit for framing. Bit robbed signalling would effectively yield a 56 kbps pipe as opposed to 64 kbps offered by ISDN PRI. However, 64 kbps (1 timeslot) of the 24 timeslots is used for signalling. This is also known as common channel signalling. As I understand it, there are three major types of services riding on T1 links:
1. Pure data T1 i.e. unchannelized T1 2. Channelized T1 and 3. ISDN PRI Wes ""Steven A. Ridder"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I think a channelized T1 sends 193 bit frames as well. 8 for each channel > plus 1 for timing = 193. > > All T1's are channelized, otherwise it would have to be some sort of > byte-synch communication, which isn't plausible. > > I think the tech you spoke to is incorrect as well. > > > ""John Neiberger"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Just when I thought I understood the T1 world pretty well we've run into > > a situation that is thoroughly confusing me. > > > > I was under the impression that channelized T1 services used 24 > > timeslots. I call that 'channelized' because it has 24 distinct > > 'channels'. It's my understanding that unchannelized T1 doesn't use the > > 24 timeslots and instead sends one giant 192-bit frame. > > > > At one of our locations we are muxing voice and data traffic onto a > > single T1. At each end we split off certain channels to a router and > > other channels over to the PBX. To do this, wouldn't the T1 *have* to > > be channelized, since we're separating the channels at the CSU/DSU? > > According to our provider, that circuit is unchannelized. If a circuit > > is truly unchannelized, how would the CSU/DSU be able to accurately > > split the T1 into two separate streams based on channel information? > > > > To be more clear, let's say we have the CSU/DSU configured to split > > channels 1-12 to the router and 13-24 to the PBX. This splitting > > function is based on the assumption that channels exist on the incoming > > T1. If they don't exist and we have one giant frame instead of 24 > > smaller frames, how could this possibly be working?? > > > > Yowza...my head hurts. > > > > John Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=47922&t=47844 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
