| Glossary: L |
| LAC |
Layer 2 Aggregation Concentrator
|
| LAN |
See Local Area Network.
|
| LANE |
LAN Emulation (ATM)
|
| LAPF |
See Link Access Procedure for Frame Relay.
|
| LATA |
See Local Access and Transport Area.
|
| Latching loopback (LLB) |
Latching loopback capability is enabled by transmitting a sequence of control codes to a loopable device to operate the loopback that will remain in operation until another control code is transmitted to release the loop.
|
| LATS |
See Loop Access Test System.
|
| LBE |
Loopback Enable
|
| LCEN |
Line Card Equipment Number
|
| LCL |
Local
|
| LGX |
Light Guided X-Connect
|
| Line |
From a switching viewpoint the loop station equipment and central office associated equipment assigned to a customer. From a transmission viewpoint the line is the transmission segment between a customer's station equipment and a switching system. In SONET a line often consists of multiple sections.
|
| Link Access Procedure for Frame Relay (LAPF) |
The data link layer protocol used by frame relay as defined in ITU-T Recommendation Q.922 and ANSI T1.618.
|
| Link Problem Determination Aid (LPDA) |
A component of NetView. Requires IBM modems or IBM DSU (a few compatibles are available).
|
| LIU |
Line Interface Unit
|
| LMOS |
See Loop Maintenance Operations System.
|
| Load coil testing |
A test method used to detect and count load coils on a circuit.
|
| Local access and transport area (LATA) |
The geographical area served by a single local telephone company.
|
| Local area network (LAN) |
A system for linking terminals programs storage and graphic devices at multiple workstations over relatively small geographic areas.
|
| Local area transport (LAT) |
A communications protocol that lets terminal emulators access VMS systems over Ethernet.
|
| LOF |
Loss of Frame
|
| Logic errors |
Any change in an originally transmitted signal (for example a bit change from a 1 to a 0). These errors can be caused by crosstalk jitter slips hardware software or human errors.
|
| Logical |
A name you can use in place of or as part of a file specification. These names are easier to remember and type than the full file specification.
|
| Long-haul facilities |
Facilities used for the inter-DSA portion of an interstate circuit (typically beyond 50 miles).
|
| Long-term testing |
A type of circuit testing in which a tester's terminal may be logged out of an operations support system without ending the test. The circuit test can be left to run for any amount of time and the results retrieved at a later date.
|
| Longitudinal redundancy check (LRC) |
A method to make sure data is received correctly. Consists of performing parity checks across the data message.
|
| Loop Access Test System (LATS) |
A relay connection matrix that provides access to individual customer four-wire local loops and/or to DS0 (64 kbps) circuits. The matrix is only at DDS hub offices.
|
| Loop length testing |
A test method that determines the length and capacitive balance of a cable pair.
|
| Loop Maintenance Operations System (LMOS) |
A testing system for voice grade telephone service that records customer trouble reports and tracks subsequent maintenance activities.
|
| Loop signaling |
A method of signaling over dc circuit paths. This method uses the metallic loop formed by the line or trunk conductors and terminating circuits.
|
| Loop Transport Testing System (LTTS) |
Hekimian’s LTTS provides remote testing of asynchronous DS1 HiCap services and facilities provided by the Smart Shelf intelligent office repeaters and enhanced HDSL transport units.
|
| Looping |
A test procedure in which the received signal returns to its source.
|
| Loss of signal (LOS) |
The absence of pulses lasting for one millisecond or more.
|
| LPBS |
Long Programmable Bit Sequence
|
| LPF |
Low-Pass Filter
|
| LSA |
Local Serving Area
|
| LSC |
Loopback Select Code
|
| LSR |
Local Service Request
|
| LTP |
Local Test Port
|
| LTPCU |
Local Test Port Control Unit
|
| LTS |
Loop Test System
|
| LULT |
Line Unit Line Termination
|
| LVDS |
Low Voltage Differential Signal
|
