ADTRAN ATLAS 800 User Manual page 176

Appendix E. Glossary
T3 Module
One of the ATLAS 800 option modules. The T3 Module provides one or two channelized T3 interfaces.
TCP/IP
Transmission Control Protocol/Internet Protocol. A set of communications protocols that encom-
passes media access, packet transport, session communications, file transfer, electronic mail, and ter-
minal emulation.
TDM
Time Division Multiplexing. A method for sending two or more signals over a common transmission
path by assignment the path sequentially to each signal, each assignment being for a discrete time
interval.
Telco
Telephone company.
Telnet
A terminal emulation protocol, part of the TCP/IP suite of protocols, that provides remote terminal-
connection services. (See also VT-100.)
TFTP
Trivial File Transfer Protocol. A simplified version of the TCP/IP file transfer protocol that does not
include password protection or user-directory capability.
trunk
A direct line between two telephone switching centers.
TSU
terminal service unit.
T-Watch PRO
The ADTRAN Microsoft Widows-based management software program designed to control TSU units
from a remote PC. It also provides limited control over the configuration of the ATLAS 800 using a
graphical user interface.
VT-100
A non-intelligent terminal or terminal emulation mode used for asynchronous communications. Used
to configure the ADTRAN ATLAS 800.
WAN
wide area network. A network that connects users across large distances.
XMODEM
An error-correcting file transfer, data transmission protocol used to transmit files between PCs. The
XMODEM protocol sends information in 128 byte blocks of data. Some sums (check sums) are done on
each block and the result is sent along with the block. If the result does not check out at the other end,
the computer at the other end sends a request (a NAK - negative acknowledgment) to retransmit that
block again). If the block checks out, the computer sends ACK (an acknowledgment). In this way, rela-
tively error-free transmissions can be accomplished.
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