Glossary
Glossary-73163-A2-GB20-10 March 1999
One of the ways in which bandwidth can be specified for multiplexer channel groups. Time slots are
specified by any number from one to twenty-four, with each time slot equal to 64 kbps.
Transmit. To send signals from a device.
Transmit Clock. V.24 circuit 114.
Transmit Data. Pin 2 of the EIA-232 interface that is used by the DTE to transmit data to the modem.
Conversely, the modem uses Pin 2 to receive data from the DTE.
A term for a digital carrier facility used to transmit a DS1 formatted digital signal at 1.544 Mbps. It is
used primarily in North America.
Unavailable Seconds. A count of one-second intervals when service is unavailable.
User Datagram Protocol. A TCP/IP protocol describing how messages reach application programs within
a destination computer.
Underwriter’s Laboratories, Inc. An organization which promotes product safety.
Voice Frequency. The part of the audio frequency range used to transmit voice sound (usually 300 Hz to
3400 Hz). This band is used by the modem for its modulated signal.
An ITU-T standard for a low-speed, 25-position, DCE/DTE interface.
An ITU-T standard for a high-speed, 34-position, DCE/DTE interface.
An ITU-T standard for local and remote diagnostic loopback tests.
An ITU-T standard for a data channel loopback (DCLB).
An ITU-T standard for a data terminal loopback (DTLB).
Wide Area Network. A network that spans a large geographic area.
External Transmit Clock. V.24 circuit 113.
An outgoing signal transmitted when a DS1 terminal has determined that it has lost the incoming signal.
time slot
TX
TXC
TXD
T1
UAS
UDP
UL
VF
V.24
V.35
V.54
V.54 Loop 2
V.54 Loop 3
WAN
XTXC
Yellow Alarm