ADTRAN 3000 - Manual (Page 138)

Appendix F. Glossary
F-4 Express 3000 User Manual 61203153L2-20
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).
Service Profile Identifier (SPID)
A unique number representing the configuration of services and
features of a particular ISDN user. The service provider assigns
one SPID to each LDN being installed. The SPID identifies the
ISDN terminal equipment to the ISDN switch at the carrier site.
terminal endpoint identifier (TEI)
An ISDN terminal device's Layer 2 address as defined in the
LAPD protocol. It is unique on a passive bus and is used to estab-
lish independent data links between the switch and each device
on the bus.
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.
X.25
Definition of the interface between user's DTE and public packet
DCE. Over a single physical link, an X.25 user can establish multi-
ple virtual circuits (either switched or permanent) each with its
own logical channel number, to different destinations.