User Manual

AS4000 Wireless Local Loop
System Overview
GSI 001
605-0000-430
Issue 1.2 Date 7/4/99
Page 6 of 16
6 ST-I1 ISDN
ISDN provides digital links into telephone network so that voice, data, text, graphics,
music, video, and other source material can be provided to end users from a single end-user
terminal. ISDN applications include high-speed image applications (such as Group IV
facsimile), additional telephone lines in homes to serve the telecommuting industry,
high-speed file transfer, and video conferencing and voice.
The AS4000 ST-I1 ISDN system provides ISDN's Basic Rate Access (BRA) service offers
two B channels and one D channel ( 2B+D). BRA B-channel service operates at 64 kbit/s
and is meant to carry user data; BRA D-channel service operates at 16 kbit/s and is meant
to carry control and signalling information, although it can support user data transmission
under certain circumstances.
2Mbit/s G.703
Q.931
(ETS 300)
Airspan
Central
Terminal
Airspan
Customer
Radio Unit
“S”
ISDN
Terminal
Adaptor
Air-Interface
V.24/V.28/
ISO 2110
X.21, V.36,
V.35
or DTMF
Telephony
Primary
Rate
Interface
Basic Rate RJ-45
“S” bus Socket
ACPSU
ACC
AS4000
Figure 4. AS4000 ISDN
6.1 ISDN Terminals
ISDN terminals come in two types. Specialised ISDN terminals are referred to as terminal
equipment type 1 (TE1). Non-ISDN terminals such as DTE that predate the ISDN
standards are referred to as terminal equipment type 2 (TE2). TE1s connect to the
Subscriber Terminal network through a four-wire, twisted-pair RJ45 interface. TE2s
connect to the ISDN network through a terminal adapter which in turn connects to the
RJ45. The ISDN TA can either be a stand-alone device or a board inside the TE2. If the
TE2 is implemented as a stand-alone device, it connects to the TA via a standard
physical-layer interface (for example, RS232C, V.24, or V.35). Up to eight ISDN user
devices can be physically attached to one circuit at the ‘S’ interface.