Nortel BCM50 2.0, Installation Manual

Page: 37 / 86

Chapter 5 ISDN overview 37
Telephony Device Installation Guide
S loops support up to seven ISDN DNs, which identify TE to the BCM50 system.
Figure 8 S reference point
T Reference Points
The T reference point connections provide a point-to-point digital connection between the ISDN
network and BCM50. Refer to
Figure 9 .
A T loop provides lines that can be shared by all BCM50 telephones, peripherals and applications,
and ISDN TE.
Figure 9 T reference point
A T loop can be used in combination with an S loop to provide D-packet service for a point-of-sale
terminal adapter (POSTA) or other D-packet device. D-packet service is a 16 kb/s data
transmission service that uses the D-channel of an ISDN line. The T and S loops must be on the
same physical module.
Inspec
t FOR
WARD
Calle
rs
Inspec
t FOR
WARD
Callers
MXP MXP
Inspec
t FOR
WARD
Callers
Inspec
t FOR
WARD
Callers
MXP MXP
Inspect F
ORW
ARD C
allers
Inspect F
ORW
ARD C
allers
MXP MXP
point-to-point
ISDN TE
ISDN TE
ISDN TE
(with terminating resistors)
ISDN TE
(with terminating resistors)
BCM50
s
s
T
ISDN
BCM50
network
connection