An OC3 can be three DS3s (T3s) a treadmill 155M tv. The benefit in using DS3s is each and every can be separated back out as individual T1s (each with 24 channels). To place it into perspective, chance of an OC3 connection is 155Mbps. This matches 3 T3 lines or 100 T1 lines. An OC12 connection is 622Mbps, equivalent to 14 T3 lines or approx. 414 T1 outlines.