On 01/26/12 4:32 PM, Nate Duehr wrote: > "T1" is a channelized synchronous telecommunications circuit type first designed in the late 60s, updated in the 70s. After removing framing bits, 1.544 Mb/s. > > "DS0" is a sub-channel of a T1 when broken up into frames. Extended SuperFrame being the typical method these days. 24 of them at 64K per channel. eek, I meant to say DS1 not DS0. Quite often these days, what people refer to as a T1 is in fact a DS1 delivered over HDSL. For all practical purposes, except the electrical signalling on the copper, the two services are equivalent, same speed, same framing. HDSL is self tuning, while classic T1 required the NIUs at each end to be tuned for the circuit, also HDSL requires fewer repeaters for longer distance circuits. -- john r pierce N 37, W 122 santa cruz ca mid-left coast