T1 is more properly known as Digital Signal 1 (DS1). T1 is a signaling framework used by T-carrier systems. T1 is now the standard signal employed by telecommunications systems in data and voice transmission between devices. T1 is the logical bit pattern employed a cross a physical T1 line.
A T1 circuit is composed of twenty-four 8-bit channels. Every channel is a 64 kbit/s DS0 multiplexed carrier circuit. T1 are also full-duplex circuits, thus, T1 circuits have net transmission and reception speeds of 1.544 Mbit/s. 1.536 Mbit/s of bandwidth is reached by accessing each of the twenty-four 8-bit DS0s 8000 times per second. This form of sampling is known as 8-kHz sampling. In addition, an extra 8 kbit/s of overhead is achieved by reason of the placement of one framing bit. Thus the total capacity of T1 signals is 1.544 Mbit/s.
Hence, T1 refers to any data circuit that achieves the original rate of 1.544 Mbit/s. Early T1 formats carried 24 pulse-code modulated, time-division multiplexed speech signals. All of these signals are embedded in 64 kbit/s streams. The extra 8 kbit/s of framing information is utilized to facilitate the synchronization and demultiplexing of the signal at the end-user device.
On the other hand, T3 circuit channels are capable of multiple T1 channels multiplexed, thus achieving a concurrent rate of 44.736 Mbit/s.
T1 and T3 signals are sent through T1 and T3 lines respectively and is fast becoming the standard in leased lines employed in the telecommunications industry. T1 lines T3 lines operate with conventional copper or next-generation fiber optic cables.
T1 and T3 technology are utilized by most business entities and large organizations to connect physically dispersed offices. Voice and/or data networking services through T1 lines are usually availed of in monthly or annual service agreements. T1 as well as T3 lines are very expensive technology not suited for residential or individual leases.