Wise TSW200E1, Manual

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TSW200E1
A device that controls data flowing to or from a computer. The term is most often used in
reference to serial communications defined by the RS-232C standard. It is usually a video terminal,
a microcomputer, etc.
Duplex
Data communication between two devices that can happen both ways, that is, from a device
to the other and vice-versa. See full-duplex.
FAS ( Frame Alignment Signal)
Used for timeslot 0 for alternated (even) frames for the 2 Mbps frames or for bit 7 of each
X.50 frame octet.
FCS ( Frame Check Sequence )
Used to detect errors based on CRC.
Full-Duplex
It is the simultaneous communication between two devices. For modems, that implies both
devices are transmitting and receiving data simultaneously. It can happen using two pairs of wires
(4-wire), where each pair is used to transmit for each modem, or using only one pair, when the
signals sent by each modem mix up in the wires, being split after reaching the destination.
HDB3
The HDB3 code is a bipolar signalling technique (i.e. relies on the transmission of both
positive and negative pulses). It is based on Alternate Mark Inversion (AMI), but extends this by
inserting violation codes whenever there is a run of four or more 0's, to prevent long runs of 0's in
the data stream, which may otherwise prevent a DPLL from tracking the centre of each bit. This
violation code must always have inverted polarity regarding the previous violation.
Homologation
After thoroughly testing a modem, assuring compatibility with industry communication
patterns, Brazilian Telebrás is the telecommunications company that allows a product to be
considered homologated. This is an essential condition for a product to be volume-produced and
used in Brazil’s huge telecommunication system.
Interface
A boundary across which two independent systems meet and act on or communicate with
each other. In computer technology, there are several types of interfaces.
ITU-T (International Telecommunication Union)
International organization within the United Nations System where governments and the
private sector coordinate global telecom networks and services. It defines the rules and standards
for telecommunications transmission. CCITT successor.
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