I did some checking on what IDSL really is -- Digital circuits from the telco can be either Point to Point (two fixed locations) or switched (like a normal telephone). They also come in different bandwidth ratings "POTS"(the standard single pair link your analog phone rides on), T1: 2 pair carrying ~1.5 meg bit/sec, T3: 45 meg bit/sec and others. The T1 line carries 24 64K (or 56K) channels, and each channel is time division muxed into a single data stream. ISDN coming in two basic flavors BRI (2x64K Bearer Channels +1x16K Data Channel) that is carried by the same single pair that POTS uses and PRI (Primary Rate Interface) 23 Bearer channels and 64K (or 56K) Data Channel. that runs over a T1 line. An ISDN PRI is the Switched equivalant of a T1. Similarly IDSL is a point to point link that uses BRI line termination gear. Apparently, the CSU/DSU used on the IDSL bonds the two bearer and the data channels of a BRI into a single 144K pipe that is terminated at your ISP (or where ever) instead of the telco switching equipment where a BRI would normally terminate. So unless your ISP is also your local telephone service provider and the line termination equipment somehow allows dynamic reconfiguration, IDSL can't provide voice dial tone service. ISDN can because it terminates in the telco switch fabric. Local loop charges for a T1 line start around $300 to $1000 a month if you need to go long distance they hit you local loop at both ends plus a mileage rate. --- Sponsor's Message -------------------------------------- TAX HELP BY PHONE. We will resolve your IRS and State Tax Problems through Fast, Easy and Affordable assistance. END your tax problems NOW! Sign-up for a free phone consultation here. http://click.topica.com/aaaaYUbz8Rp2bAfyICc/edebt ------------------------------------------------------------ -- Visit http://www.ShareTheNet.com for info about ShareTheNet Visit http://www.topica.com/lists/sharethenet for info about this list ___________________________________________________________ T O P I C A http://www.topica.com/t/17 Newsletters, Tips and Discussions on Your Favorite Topics
