PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 253

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

Note 74: These Parameter shall apply to the complete temperature range and life time.
External Oscillator
Frequency:
Frequency tolerance:
In this case the requirements for the master clock are the same as the requirements in
the LT case. See "Master Clock", page 281 for details.
7.2
This section gives an example for using the S/G bit and BAC bit control feature (see
section 3.9, page 90) for D-channel arbitration in PBX applications with the PEB 20550
(ELIC
The S/G bit on DOUT (downstream) and the BAC bit on DIN (upstream) can be used to
allow D-channel arbitration similar to the operation of the Upn interface realized with the
OCTAT-P and the ISAC
The PBX line card using the ELIC
terminals. As soon as one terminal T requests the D-channel, e.g. for signalization, all
other terminals receive a message indicating the D-channel to be blocked for them. The
request is done with the BAC bit. At terminal T the BAC bit is set and the IEC-Q transfers
the need for the D-channel to the LT side. There, the HDLC-controller is assigned to the
appropriate IOM
of the S/G bit, the terminal begins to send D-channel messages.
Note that this procedure is somewhat different from the operation of the OCTAT-P used
with the ISAC
indicates the need for the HDLC-controller. This implies that any other terminal, that
incidentally sent a HDLC-message the same time, can be stopped before the message
is lost in case the HDLC-controller is not available. The U-interface featured by the
IEC-Q is not able to transfer the available/blocked information often enough to ensure
this. Hence, it is necessary to indicate a D-channel access by the terminal in advance.
"In advance" actually means about 14 ms.
Giving MON-0 25
access at the NT side to be on "STOP". As one EOC-message is transmitted via the
EOC-channel once every 6 ms, the S/G bit on IOM
If the 4 channel PEB 24911 (DFE-Q) is used in the LT, a PEB 20550 (ELIC
arbitrate the D-channel via the C/I command as known from the OCTAT-P and QUAT-S
devices. Please refer to the PEB 24911 Data Sheet for detailed information on this.
Semiconductor Group
®
) used in the Line card.
The temperature range depends on the version used. For PEB 2091 it is
between 0°C and 70°C, for the PEF 2091 it is between -40°C and 85°C.
Applications with EPIC
®
-P TE. There, the begin of the upstream D-channel data transfer itself
®
-2-channel. Once this is done and indicated to the terminal by means
H
at the LT during Transparent operation will cause the D-channel
®
-P TE. The basic function is as follows:
15.36 MHz
80 ppm
®
®
assigns one HDLC controller to a number of
on the Line Card (PBX)
253
®
-2 can be set in 6 ms intervals.
Application Hints
Data Sheet 01.99
PEB 2091
PEF 2091
®
) can