NOTE: The key word is bits not bytes. Bits are smaller in size than bytes, a bit is One/1 and a byte can be 4, 8, 10, 12, 16, so on and so forth depending on the subject we are talking about. The telecommunications industry uses bits, hence TelecomBits.com, now you know where we got our name. Please never confuse the two. From a PC standpoint 8 bits equal one byte and 1 byte equals 8 bits.
DS0 transmits data at a rate of 64,000 bits per second or 64 Kbps and is a channel within a T-Carrier Circuit like a T1, T2, T3, T4 or Optical Carriers like an OC3.
T1 or DS1 is the equivalent of 24 phone lines or 24 DS0's. A T1 can handle 1.5 million bits per second or 1.5Mbps.
T2 or DS-2 is the equivalent of 4 T1 Lines. The capacity is 6.3 million bits per second or 6.3 Mbps
T3 or DS-3 is equal to 28 T1 Lines. The capacity is 45 million bits per second or 45 Mbps.
T4 or DS-4 is the equivalent of 6 T3 Lines. The capacity is 274 million bits per second or 274 Mbps.
OC-1 or also known as the term SONET. An OC1 uses ATM switches, as OC-X does and runs at 51 million bits per second or 51 Mbps. OC-X uses optical fiber
OC-3 is the equivalent of 155 million bits per second or 155 Mbps.
OC-12 transmits 600 million bits per second or 600 Mbps.
OC-48 transmits 2.4 gigabits per second or 2.4 Gbps.
ATM or Asynchronus Transfer Mode is a very expensive switching solution that is used in deliver OC-3 and OC-12 lines.