CCNA Cisco Certified Network Associate Study Guide - FTP Server

FIGURE 10.7 ISDN BRI reference points and terminal equipment
TE1
TE1
NT1
bri0
S/T
bri0
U
ISDN Terminals
Native ISDN interface—int bri0
NT1
TE2
Integrated Services Digital Network (ISDN) 507
R
S0
NT1
Devices connecting to the ISDN network are known as terminal equipment
(TE) and network termination (NT) equipment. There are two types of each:
TE1 Terminal equipment type 1 refers to those terminals that understand
ISDN standards and can plug right into an ISDN network.
TE2 Terminal equipment type 2 refers to those that predate ISDN standards.
To use a TE2, you have to use a terminal adapter (TA) to be able
to plug into an ISDN network.
NT1 Network termination 1 implements the ISDN Physical layer specifications
and connects the user devices to the ISDN network.
NT2 Network termination 2 is typically a provider’s equipment, such as
a switch or PBX. It also provides Data Link and Network layer implementation.
It’s very rare at a customer premises.
TA Terminal adapter converts TE2 wiring to TE1 wiring that then connects
into an NT1 device for conversion into a two-wire ISDN network.
S/T
NT1
Nonnative ISDN interface—int serial 0
(EIA/TIA-232, V.35, X.21)
Service provider
network