Zhone IMA CS-200 System Reference Manual page 285

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
HSU port
High-Speed Unit port (one of the data ports for this system).
HMI
Host Management Interface
HOM
HDSL OEM Module
ICMP
Internet Control Message Protocol
IEC
Inter-exchange Carrier (also called IXC)
IMUX
Inverse Multiplexer
IMUX port
A resource port that gives users access to the ISDN network for bandwidth-on-demand
applications.
inverted a-law
A variation of a-law encoding that provides a higher ones density on E1 lines.
IP
Glossary -11