Verilink XEL XSP-100 SHARK IAP (9SA-USRS-9.0R1.02) Product Manual - Manual (Page 250)

Chapter 10 Chapter 10.Appendix A: Glossary
Appendix: 10-8 XEL P/N & Release: 9SA-USRS-9.0R1.02 SHARK™ IAD User's Guide
G
ROUND
S
TART
/L
OOP
S
TART
Two common telephone trunk signaling schemes. In ground start signaling, the device at one
end of the connection grounds one side of the line and the device at the other end detects the
presence of the ground. In loop start signaling, one device closes the loop and the device at the
other end detects the resulting current flow. PBX systems usually are connected to ground start
trunks, and single telephone lines and key systems to loop start trunks. The XSP - 100 supports
both, and automatically detects for channel bank which signaling scheme is used on a line-by-
line basis.
- H -
HARDWARE
HANDSHAKE
Method of flow control using two control lines, usually Request to Send (RTS) and Clear to
Send (CTS).
HDLC High-level Data Link Control. A communications protocol for point-to-point and multipoint
communications that reduces the likelihood of errors.
HDSL High-data-rate Digital Subscribe Line. Modems on either end of one or more twisted pair wires
that deliver T1 or E1 speeds. T1 requires two lines and E1 requires three. Typical maximum
distances are 12000 feet of repeater-less UTP (Unshielded Twisted Pair) wire at T-1 speeds of
1.544 Mbps with full duplex transmission. Compare ADSL, SDSL.
HEADER
The portion of a packet, preceding the actual data, containing source and destination addresses
and error-checking fields.
HOP
A unit for measuring the number of routers a packet has passed through when traveling from one
network to another.
HOP COUNT
Distance, measured in the number of routers to be traversed, from a local router to a remote
network. See metric.
H
OST
N
UMBER
The low bits of an IP address which corresponds to those bits in the associated subnet mask
which have 0’s.
HTTP HyperText Transfer Protocol. The protocol used for communication between World Wide Web
servers and Web browsers.
HUB
Another name for a repeater.
- I -
ICMP Internet Control Message Protocol. A low-level protocol that supports functions such as echo
requests and “host not available” messages. As specified in RFC-792, ICMP provides a number
of diagnostic functions and can send error packets to hosts. ICMP uses the basic support of IP
and is an integral part of IP
.