t1 - Computer Definition
Corresponds to DS-1 (Digital Signal level One) in the North American digital signal hierarchy.The fundamental level of the T-carrier digital carrier system.A T1 system comprises circuitterminating equipment in the form of a combination of a channel service unit (CSU) and data service unit (DSU) that jointly serve to interface a device to a full-duplex (FDX) four-wire digital circuit and to perform various signal-formatting, signal-timing, monitoring, and diagnostic functions.T1 operates at a signaling rate of 1.544 Mbps, which supports a frame rate of 8,000 frames per second (fps), with each frame comprising a framing bit followed by 192 bits of user payload, at least potentially.The framing bits are used for synchronization and, in some cases, for monitoring, diagnostic, and other network management purposes.The 192 bits of user payload are organized into 24 time-division multiplexed (TDM) time slots, each of which is eight bits wide. See Figure T-1. At a rate of 8,000 fps, each time slot is repeated 8,000 times per second, which translates into a DS-O channel at 64 kbps (8 bits
(Transaction plus 1 day) In financial processing, the ability to complete a stock transaction within one day of the day it was made, which includes settlement, payment and transfer of ownership.
(2) A 1.544 Mbps point-to-point, dedicated, digital circuit provided by the telephone companies. With the monthly cost typically based on distance, T1 lines are widely used for connecting an organization's PBX to the telephone company or a local network (LAN) to an Internet provider (ISP). They are also used for Internet access in buildings that have no DSL, cable or fixed wireless coverage. T1 lines were widely used for connecting branch offices, but most have been supplanted by virtual private networks (VPNs) over the Internet. It Started in the 1960s The first T1 line was tariffed by AT&T in January 1983. However, in the early 1960s, AT&T started the move to digital transmission, and T1 lines were deployed in intercity trunks to improve signal quality and make more efficient use of the network. T1 Anatomy A T1 line uses two wire pairs (one for transmit, one for receive) and time division multiplexing (TDM) to interleave 24 64-Kbps voice or data channels. The standard T1 frame is 193 bits long, which holds 24 8-bit voice samples and one synchronization bit with 8,000 frames transmitted per second. T1 is not restricted to voice or 64 Kbps data streams. Channels may be combined and the total 1.544 Mbps capacity can be broken up as required. See DS, T-carrier, bipolar transmission, D4 and ESF. 64 Kbps T-Carrier Total Speed Channels T1 1.544 Mbps 24 T2 6.312 Mbps 96 T3 44.736 Mbps 672