Wise TSW200E1, Manual

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TSW200E1
9 - Glossary of Technical Terms
2-wire
Communication in which two modems are interconnected by only a wire pair. See full-
duplex.
4-wire
Communication in which two modems are interconnected by two wire pairs. See full-
duplex.
AIS ( Alarm Indication Signal)
Alarm Indication Signal: signal that gets active when any alarm condition arises.
BPS (Bits per second) or bits/s
Number of bits transmitted or received per second
CAS ( Channel Associated Signalling)
Used for 2 Mbps PCM30 and PCM30C.
CCITT
Abbreviation of C omité C onsultatif I nternational T éléphonique et T élégraphique , an
organization that sets international communications standards. CCITT, now known as ITU (the
parent organization) has defined many important standards for data communications.
CPE
(Pronounced as separate letters) Short for c ustomer p remises e quipment , communications
equipment that resides on the customer's premises (i.e., it is owned or leased by the customer).
Client-owned equipment.
CRC ( Cyclic Redundancy Check)
CRC-4 consists in an error detection method used for 2 Mbps frames, where for each
transmitted data block a set of bits is added, which allows error detection within the block. A CRC-4
(C1 C2 C3 C4) word, placed at the N
sub-multiframe , is the remainder of the operation:
multiplication by x
4
and division by the generated polynomial x
4
+ x + 1, of the polynomial
representing the N-1 sub-multiframe . In this process, the C1 bit is defined as the most significant bit
of the remainder and C4 is the least significant bit.
DCE ( Data Communications Equipment)
A device that communicates with a Data Terminal Equipment (DTE) device in RS-232C
communications. Usually a modem.
DTE (Data Terminal Equipment )
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