T1/DS-1 Cables

Belden announces the addition of four T1/DS-1 cables to its interconnect and cross-connect product offering. These cables have been designed to meet today's applications inthe central office. All of Belden T1 cables are suitable for use inside central office buildings or in controlled environment vaults (CEVs) where temperature and humidity are maintained within a relatively constant range. The T-carrier system, introduced by Bell System in the U.S. in the 1960s, was the first successful system that supported digitized voice transmission. The original transmission rate (1.544 Mbps)in the T1 line is in common use today in Internet Service Provider (ISP) connections to the Internet. Another commonly installed service is a fractional T1 line, which is the rental of some portion of the 24 channels in a T1 line, with the other channels going unused.

Digital Carrier Systems
Several steps are taken in the transmission process to maximize the number of communication channels available. One of the most significant is the combining of multiple signals on one channel by a process known as multiplexing. This is particularly easy to apply to digital or A/D converted analog signals. The first level, known as T1, uses a carrier frequency of 1.544 Mb/s and is capable of handling 24 standard (3100 Hz bandwidth) voice channels. This system is widely used for short-haul carrier transmission and can operate over standard twisted pair cables.

A T1 line is capable of handling up to 1.536 Megabits/sec of data so it can be used with wideband data terminals. Digital signals on a T1 carrier are coded alternate bipolar, and a 50% duty cycle pulse, in which the leading and trailing 25% of the original pulse are not included. This reduces the power required as well as minimizing crosstalk.
System ............................................T1
Rate Mb/s ...................................1.544
Voice Channels...............................24
Cable Type ...................Paired Cables
Notes ...Basic North American System

Dual Insulations
Belden's 7837A (one pair) and 7838A (two pair) are insulated with solid polyolefin for the base and Belden's Datalene foam for the outer layer to enhance electrical characteristics and allow for RJ-45 connectorization. Belden's 7839A (six pairs) and 7840A (twelve pairs) are insulated with a flame retardant polyolefin. Belden's use of Western Electric Color Coding simplifies the installation and termination process with distinct conductor identification.

Shielding
Belden's T1 cables feature foil shields to provide superior shield effectiveness, greater flexibility and light weight; and terminate easily with the drain wire. While a noise-free signal is a convenience for a phone conversation, it's vital for data transmission — an erroneous blip here or there, for example, could erase a digit and change your checking account balance from $5,000 to $500. Belden's Beldfoil shielding and superior crosstalk characteristics are designed to ensure signal integrity by reducing electromagnetic interference which can corrupt data. Belden's crosstalk performance allows you to run multiple T1 transmissions over a single cable, preventing the lines from interfering with each other.

Telcordia (Bellcore) GR-137-CORE
Belden's family of T1 cables meet all of the requirements of the Telcordia specifications further ensuring maximum cable performance.

Belden Electronics Division, 2200 U.S. 27 South, P.O. Box 1980, Richmond, IN 47374-7279. Tel: 765-983-5200; Fax: 765-983-5294.