Technical data

www.westermo.com Theoretical and general applications 151
Ground currents Current that flows in the ground conductors between two
systems with different ground potential.
GSM Global System for Mobile communication, a standard for digital
wireless communication.
Half duplex Two way communication.
Handover Name for switching between base transceiver stations when
communicating via the GSM network.
Handshaking Confirmation and status signals sent between communicating
equipment to check the data flow.
Hayes commands A group of commands for communications with
telephone modems.
Hub A simple device that enables network segments to be connected.
When a packet is received on one port it is sent to all ports on
the Hub.
IEEE802.1d Spanning Tree Protocol standard. A basic method of providing
network redundancy.
IEEE802.1p Packet prioritization standard. A method of prioritizing packets
by adding a priority tag to the packet.This enables the packet
to override low priority traffic.
IEEE802.3 The standard specification for Ethernet.
IEEE802.3x A standard for Ethernet flow control. A way to throttle the speed
of a switch if the buffer is about to overflow. A packet is sent that
requests the sending switch to pause sending packets for a period
of time.
Interface A defined standard for signals, electrical levels and inter-
connection.
Interface Modem that converts signals between two different
Converter interfaces, for example, between RS-232 and RS-422/485.
IP The IP (Internet Protocol) is responsible for moving packets of
data from node to node without any regard for the content. IP
forwards each packet based on a four byte destination address
(the IP address).
B A C K