PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 255

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

PEB 2091
PEF 2091
Application Hints
U-interface. As an EOC-message can start once every 6 ms and will take 6 ms to be
transmitted, TD2 will be 12 ms in the worst case.
TD1 is at minimum 7.5 ms depending on the location of the superframe at the time the
HDLC-controller is requested by the terminal. This delay is necessary because instead
of receiving an EOC-message "go" as requested, the terminal could as well receive the
EOC message "stop" because the HDLC-controller was assigned to an other subscriber
just before .
Flags as Interframe Fill
The influence to the upstream D-channel can be disabled while the control of the S/G-bit
via EOC-messages and via the BAC bit is still given as described above by setting
SWST:BS to "0", SWST:SGL to "1" and ADF:CBAC to "1". This is useful when having a
controlling device in the terminal, that is able to send the interframe timefill "flags".
Semiconductor Group
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Data Sheet 01.99