John, You make a good point that channelized T-1s are all but unheard of. However, the term "clear channel" doesn't mean unchannelized. It means that the DS0s are the full 64 kbps, as opposed to the older bit-robbed 56 kbps DS0.
Scott John Neiberger wrote: > > This is not quite right. Yes, ISDN PRI is physically a > channelized T-1. > In this case you have 23 data bearing channels and one > signalling > channel. > > For data, you can order a channelized T-1 if you need to. This > gives > you 24 channels available for data, but they are entirely > separate > channels. This probably isn't very common. You will see this > sort of > thing with a DS3 quite a lot, though. For example, we have a > few > channelized DS3s coming into our building here. On our end we > demultiplex them, splitting them out to their individual DS1 > channels. > > The other data option which is most common is a clear channel > T-1. > This is not channelized and provides a single 'channel' at > 1.544 Mbps. > If you were to order a point-to-point circuit between > locations, this is > what you'd order. > > HTH, > John > > >>> "Chris Charlebois" 3/12/02 12:43:03 > PM >>> > T-1 is the layer 1 standard. ISDN PRI uses T-1 for layer 1 > connectivity. > Therefore, whenever you say ISDN PRI, you are referring to T-1. > However, > not all T-1's are ISDN PRI. > > The "other" T-1 is referred to as CAS, channel associated > signaling > and, as > far as I know, is only used for voice. It allows 24 channels of > sampled > voice. ISDN PRI (aka common channel signaling) is a digital > standard > and > supports 23 64k "B" channels (that can carry voice or data) and > 1 64k > "D" > channel that carries control information. Voice over ISDN PRI > has the > advantage of a dedicated control channel for troubleshooting and > additional > call information from the telephone provider. However, it has > 1 less > channel. > > So if you are ordering a data T-1, your only choice is ISDN PRI. > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=37999&t=37983 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
