How many T1's per STS?

In a T-carrier system, one T1 line consists of 24 voice channels, each capable of carrying 64 kbps, resulting in a total bandwidth of 1.544 Mbps. An STS-1 (Synchronous Transport Signal level 1) has a data rate of 51.84 Mbps. Therefore, you can fit approximately 32 T1 lines (or 768 voice channels) within one STS-1.