| Glossary: U |
| U-DSL |
U Interface - Digital Subscriber Loop
|
| UBRITE |
U Interface - Basic Rate Interface Transmission Equipment
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| UDP |
User Datagram Protocol
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| UFT |
Uniform File Transfer
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| UMC |
Unassigned MUX Channel
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| UML |
Unified Modeling Language
|
| Unavailable seconds (UASs) |
Count of seconds for which the monitored entity is unavailable. The monitored entity is deemed unavailable from the onset of ten contiguous SESs (for paths only) and becomes available from the onset of ten contiguous seconds without an SES.
|
| Unipolar |
A signal stream in which all one bits are the same voltage polarity. Zero bits normally are zero volts.
|
| Unipolar return-to-zero |
A unipolar signal with a 50 percent duty cycle for each pulse.
|
| UNIX™ |
An interactive time-sharing operating system for computers for running data processing and for running telephone systems. Multiple programs can run simultaneously by multiple users using a single computer.
|
| UPC |
Usage Parameter Control
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| User-Defined Macro |
A REACT 2000 option allowing a tester to record the steps taken to test a circuit and to later play back those steps automatically to test another circuit of the same type.
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| User-to-Network Interface (UNI) |
The reference point where the protocols for compatibility between customer premises equipment (CPE) and a carrier network must be defined. A UNI specification defines in detail the Layer 1 and Layer 2 and perhaps Layer 3 protocols which are required for CPE and carrier equipment to interoperate.
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| USTA |
United States Telephone Association
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