Zhone IMACS 8000 User Manual page 769

Foreign Exchange - Office, performs analog to digital and digital to analog transmission at the
CO.
FXO Card
One of the voice cards for this system
FXS
Foreign Exchange - Subscriber or Station, an interface at the end of an FX line connected to a
telephone or PBX. Performs digital to analog and analog to digital transmission at the station
end.
FXS Card
One of the voice cards for this system
Ground
A physical connection to the earth, chassis, or other reference point
HDB3
High-Density Bipolar Order of 3, three-zero maximum coding for E1 lines. Provides a fourth
zero violation for data bytes.
HDLC
High-Level Data Link Control (bit-oriented protocol)
HDSL
High-bit rate Digital Subscriber Line
hlink
A proprietary format for subrate data when using the ADPCM card.
HSU Card
High-Speed Unit Card (one of the data cards for this system).
HMI
Host Management Interface
HOM
Reference Guide E-11