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=37989&t=37983 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
