Specifications

Appendix F. Glossary
61203153L3-20 Express 3000 SP User Manual F-3
interrupt request (IRQ)
A system of implementing computer processor interrupts (a sus-
pension of one process to initiate another process--usually tempo-
rarily).
plain old telephone service (POTS)
The basic analog phone service. Does not include ISDN or calling
features such as caller ID, etc.
Point-to-Point Protocol (PPP)
A standard method of transporting multiprotocol datagrams over
point-to-point links. PPP facilitates connections through a wide
variety of hosts, bridges, and routers. PPP is intended for simple,
bidirectional, full duplex links transporting packets between
peers.
Ringer Equivalence Number (REN)
A number assigned to an individual piece of telephone equipment
indicating that the unit has met certain requirements and guide-
lines. If several units are using the same line, the total value of the
REN should not exceed 5.0 (see also Load Number).
universal asynchronous receiver/transmitter (UART)
An integrated circuit device that receives serial data and converts
it into parallel form for transmission, and vice versa.
V.120
A 1996 standard for ISDN support of DTE with V-series interfaces
with provision for statistical multiplexing.