Editing Digital Signal 1 (section)

==Overview==
T1 refers to the primary digital telephone [[carrier system]] used in North America. T1 is one line type of the [[Pulse-code modulation|PCM]] T-carrier hierarchy. T1 describes the cabling, signal type, and signal regeneration requirements of the carrier system.

{| class="wikitable"
|+PCM T-Carrier Hierarchy<ref>Fiber Optics Standard Dictionary; T1 Overview (Motorola, 1996)</ref><ref>{{cite book
|url=https://books.google.com/books?id=ZCYBCAAAQBAJ&q=ds5+megabit&pg=PA1207
|last=Weik|first=Martin|publisher=Springer Science & Business Media|date=2012|title=Fiber Optics Standard Dictionary
|isbn=9781461560234|access-date=6 August 2015}}</ref><ref>{{cite web|url=http://www.optimumdata.com/shop/files/motorola/ft100m/16apd.pdf|title=FT100 M User's Guide|publisher=Motorola Inc.|date=1996|access-date=25 June 2016|archive-url=https://web.archive.org/web/20160304083142/http://www.optimumdata.com/shop/files/motorola/ft100m/16apd.pdf|archive-date=4 March 2016|url-status=dead}}</ref>
|-
! Digital Signal Designation
! Line rate
! Channels (DS0s)
! Line
|-
| DS0
| 64 kbit/s
| 1
|
|-
| '''DS1'''
| 1.544 Mbit/s
| 24
| T1
|-
| DS1C
| 3.152 Mbit/s
| 48
| T1C
|-
| DS2
| 6.312 Mbit/s
| 96
| T2
|-
| [[Digital Signal 3|DS3]]
| 44.736 Mbit/s
| 672
| T3
|-
| [[DS4/NA|DS4]]
| 274.176 Mbit/s
| 4032
| T4
|-
| DS5
| 400.352 Mbit/s
| 5760
| T5
|}

The signal transmitted on a T1 line, referred to as the DS1 signal, consists of serial bits transmitted at the rate of 1.544&nbsp;Mbit/s. The type of line code used is called [[Bipolar encoding#Alternate mark inversion|Alternate Mark Inversion]] (AMI). Digital Signal Designation is the classification of [[Carrier signal|digital bit rates]] in the [[digital multiplex hierarchy]] used in transport of telephone signals from one location to another. DS-1 is a [[communications protocol]] for [[multiplexing]] the [[bitstream]]s of up to 24 telephone calls, along with two special [[bit]]s: a framing bit (for [[frame synchronization]]) and a maintenance-signaling bit, transmitted over a digital [[carrier system|circuit]] called [[T-carrier|T1]]. [[T-carrier|T1]]'s maximum data [[Bit rate|transmission rate]] is 1.544 megabits per second.