pef20550 Infineon Technologies Corporation, pef20550 Datasheet - Page 343

• Manufacturer Part Number: pef20550
• Description: Extended Line Card Interface Controller Elic
• Manufacturer: Infineon Technologies Corporation

5.9.2
Trunk lines connect the PBX to the central office (CO) network. Figure 117 gives an
overview of the different access possibilities to the central office.
One possibility is to use analog a/b lines. This is the most uncomplicated way since no
clock recovery from the CO is required, i.e. the PBX operates with a free running crystal
oscillator. The t/r access to the CO can easily be realized with one or several SICOFI
or SICOFI-4 codec/filter devices, which allow the connection of two or four analog lines
per chip.
If an access to the ISDN world is desired, two options are possible:
For small PBXs, with only few external lines, one or several Basic Rate ISDN (BRI)
connections are best suited. Each BRI connection provides a capacity of two B channels
of 64 kBit/s and one D channel of 16 kBit/s. The BRI connection is usually performed via
the T interface to the Network Terminator 1 (NT1). The T interface is physically identical
to the S interface, all Siemens S
be used for that purpose. A PBX can also be connected directly via the U
the CO. In this case an IEC-Q device (2B1Q encoding) or an IEC-T (4B3T encoding) can
be used as layer-1 device.
Figure 117
Overview of Trunk Line Applications
Semiconductor Group
PCM/Signaling
Backplane
IOM
PCM
®
-2 Trunk Line Applications
ELIC
HDLC
R
PBX Trunk Line Card
0
IDEC
IOM -2
interface devices (QUAT-S, SBCX, ISAC-S, SBC) can
µP
R
R
343
SICOFI -2
SICOFI -4
SBCX
QUAT-S
FALC54
IECQ
R
R
S
T
2m
NT1
NT1
U
t/r
t/r
k
Application Hints
U
U
U
k
k2
g2
k
Analog
Line
Analog
Line
Basic Rate
ISDN
Basic Rate
ISDN
Primary Rate
(CEPT, T1)
Central Office
PEB 20550
- interface to
PEF 20550
ITS08097
01.96
-
2