Digital Signal 3
Encyclopedia
A Digital Signal 3 is a digital signal level 3 T-carrier
. It may also be referred to as a T3 line.
and connectors. Cables or connectors which are 50 ohm or which significantly deviate from 75 ohms will result in signal reflection
s which will lower the performance of the connection, possibly to the point of not working. Bellcore standard GR-139-CORE defines type 734 and 735 cables for this application. Due to losses, there are differing distance limitations for each type of cable. Type 734 has a larger center conductor and insulator for lower losses for a given distance. The BNC connector
s are also very important as are the crimping and cable stripping tools used to install them. Trompeter, Cannon, Amphenol, Kings, and Canare make some of the true 75 ohm connectors known to work. RG-6
or even inexpensive RG-59
cable may work temporarily when properly connectorized, though it does not meet telephony technical standards.
(which is distance-sensitive) and the port (or the price the carrier charges to access the internet through their proprietary network).
T-carrier
In telecommunications, T-carrier, sometimes abbreviated as T-CXR, is the generic designator for any of several digitally multiplexed telecommunications carrier systems originally developed by Bell Labs and used in North America, Japan, and South Korea....
. It may also be referred to as a T3 line.
- The data rate for this type of signal is 44.736 Mbit/s.
- This level of carrier can transport 28 DS1Digital Signal 1Digital signal 1 is a T-carrier signaling scheme devised by Bell Labs. DS1 is a widely used standard in telecommunications in North America and Japan to transmit voice and data between devices. E1 is used in place of T1 outside North America, Japan, and South Korea...
level signals within its payload. - This level of carrier can transport 672 DS0Digital Signal 0Digital Signal 0 is a basic digital signaling rate of 64 kbit/s, corresponding to the capacity of one voice-frequency-equivalent channel...
level channels within its payload. - Such circuits are the usual kind between telephony carrierTelephone companyA telephone company is a service provider of telecommunications services such as telephony and data communications access. Many were at one time nationalized or state-regulated monopolies...
s, both wired and wirelessWirelessWireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...
, and typically by OC1 optical connections.
Cabling
DS3 interconnect cables must be made with true 75 ohm coaxial cableCoaxial cable
Coaxial cable, or coax, has an inner conductor surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting shield. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis...
and connectors. Cables or connectors which are 50 ohm or which significantly deviate from 75 ohms will result in signal reflection
Signal reflection
Signal reflection occurs when a signal is transmitted along a transmission medium, such as a copper cable or an optical fiber, some of the signal power may be reflected back to its origin rather than being carried all the way along the cable to the far end. This happens because imperfections in the...
s which will lower the performance of the connection, possibly to the point of not working. Bellcore standard GR-139-CORE defines type 734 and 735 cables for this application. Due to losses, there are differing distance limitations for each type of cable. Type 734 has a larger center conductor and insulator for lower losses for a given distance. The BNC connector
BNC connector
The BNC connector ' is a common type of RF connector used for coaxial cable. It is used with radio, television, and other radio-frequency electronic equipment, test instruments, video signals, and was once a popular computer network connector. BNC connectors are made to match the characteristic...
s are also very important as are the crimping and cable stripping tools used to install them. Trompeter, Cannon, Amphenol, Kings, and Canare make some of the true 75 ohm connectors known to work. RG-6
RG-6
RG-6/U is a common type of coaxial cable used in a wide variety of residential and commercial applications. The term "RG-6" itself is quite generic and refers to a wide variety of cable designs, which differ from one another in shielding characteristics, center conductor composition, and...
or even inexpensive RG-59
RG-59
RG-59/U is a specific type of coaxial cable, often used for low-power video and RF signal connections. The cable has a characteristic impedance of 75 ohms. The 75 ohm impedance matches a dipole antenna in free space. "RG" was originally a unit indicator for bulk radio frequency cable in the...
cable may work temporarily when properly connectorized, though it does not meet telephony technical standards.
DS3 Pricing
DS3 service is provided to businesses in the United States through ILEC and CLEC communication providers. The price, much like a T1 (or DS1) line, has two primary components: the loopLocal loop
In telephony, the local loop is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the carrier or telecommunications service provider's network...
(which is distance-sensitive) and the port (or the price the carrier charges to access the internet through their proprietary network).