Telos TWOx12 - Page 206

TELOS TWOX12 USER’S MANUAL
GLOSSARY OF TELEPHONE TERMINOLOGY
APPENDIX 4 194
latest round of de-regulation the usual IEC companies are being allowed to compete in
the IntraLATA long distance market and LECs are beginning to be permitted to handle
InterLATA calls.
LDN
- Listed Directory Number. When a number of Telco channels share the same
hunt group it is customary to give out only one phone number for the group, although
generally each channel will have its own number. The number given out is the “Listed
Directory Number” since that is the number that would be listed in the Telephone
Directory and given to customers. See also DN and Hunt Group.
LEC
- Local Exchange Carrier. Your local telephone service provider which is either an
RBOC or an Independent. In other words, a traditional phone company. In contrast to
CLEC or IEC.
Line
- An electrical connection between a telephone service provider’s switch (LEC or
CLEC) and a telephone terminal or Key system. An electrical connection between a
telephone service provider’s switch and another switch is called a trunk. Note that some
type of physical lines offer more than one channel. I.E. a BRI circuit has 2 channels,
called B channels. This term is a confusing one. See Channel. See also Station Line.
Line card
- The circuit in the Telco switch to which your line is connected. On an
ISDN circuit the line card performs a role analogous to the NT1 in adapting and
equalizing the circuit.
Listed Directory Number
- See LDN
Local Access and Transport Area
- See LATA.
Local Exchange Carrier
- See LEC and CLEC.
Long Distance
- 1) If your local Telco is a former Bell Operating Company then any
call outside of your LATA or any Interstate call is considered long distance and is
handled by an IEC. 2) If your local phone company is an independent then only
interstate and inter-phone company calls are considered long distance. The above is
true regardless of whether you are referring to a dedicated line or a dial up call. 3)
However, under the current state of deregulation, toll calls within a LATA may now be
covered by the IEC, and in some cases RBOCs are being permitted to handle
InterLATA calls.
Loop
- The telephone circuit from the CO to the customers premises. Generally refers
to a copper cable circuit.
Loop Qualification
- Process of actually measuring the loss on a prospective ISDN line
to see if it can be used for ISDN service. The actual loss on the line is the determining
factor whether ISDN service can be offered without a repeater. Generally ISDN is
available up to 18,000 feet from the serving Central Office. It may not be available
within this range, or may be available further from the CO. Only a loop qualification
can tell for sure. Not all Telcos will extend ISDN lines with repeaters.
Loop Start Line
- A plain old telephone line. The telephone terminal signals the “off
hook” condition by allowing DC current to flow. See Ground Start Trunk. See also
Glare.
Loop Start Trunk
– A plain old telephone line connected to a PBX switch. See Loop
Start Line. The PBX signal the “off hook” condition by allowing DC current to flow.
Ground Start Trunks are generally preferred for use on PBXs to prevent glare. See
Ground Start Trunk. See also Glare.