E-carrier is used in place of T-carrier outside the United States, Canada, Japan, and South Korea.
[a] T1 refers to the primary digital telephone carrier system used in North America.
One framing bit adds 8 kbit/s of overhead, for a total of 1.544 Mbit/s, calculated as follows: DS1 is a full-duplex circuit, concurrently transmitting and receiving 1.544 Mbit/s.
Due to the unique bit sequences exchanged, the framing schemes are not compatible with each other.
Connectivity refers to the ability of the digital carrier to carry customer data from either end to the other.
There are three defined alarm indication signal states, identified by a legacy color scheme: red, yellow and blue.
For SF framed signals, the user bandwidth is manipulated and "bit two in every DS0 channel shall be a zero.
Simultaneously, the customer data is often coerced to a 0x7F pattern, signifying a zero-voltage condition on voice equipment.
Additionally, for voice T1s there are two main types: so-called "plain" or Inband T1s and PRI (Primary Rate Interface).
The name T1 came from the carrier letter assigned by AT&T to the technology in 1957, when digital systems were first proposed and developed, AT&T decided to skip Q, R, and S, and to use T, for time division.
Destined successors of the T1 system of networks, called T1C, T2, T3, and T4, were not commercial successes and disappeared quickly.
Since the practice of naming networks ended with the letter T,[8] the terms T1 and DS1 have become synonymous and encompass a variety of services including voice, data, and clear-channel pipes.
Running Ethernet networks between geographically separated buildings is a practice known as "WAN elimination".
The semiconductor chip contains a decoder/encoder, loop backs, jitter attenuators, receivers, and drivers.
Additionally, there are usually multiple interfaces and they are labeled as dual, quad, octal, etc., depending upon the number.
The transceiver chip's primary purpose is to retrieve information from the "line", i.e., the conductive line that transverses distance, by receiving the pulses and converting the signal which has been subjected to noise, jitter, and other interference, to a clean digital pulse on the other interface of the chip.