PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 148

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

Semiconductor Group
4.4.2.2
The transition criteria used by the IEC-Q are described in the following sections. They
are grouped into:
– C/I-commands
– Pin states
– Events related to the U-interface
– Timers
C/I-Commands
AR
AR0
ARX
ARL
DC
Transition Criteria in LT Modes
Activation Request
The IEC-Q is requested to enter the power-up state and to start an
activation procedure by sending the wake-up signal TL.
Activation Request with "ACT" bit = (0)
The IEC-Q is requested to enter the power-up state and to start an
activation procedure by sending the wake-up signal TL. After "EQ Training"
the state "Line Active" will be entered independent of the "ACT" bit.
Evaluation of the "ACT" bit is disabled when AR0 is received and enabled
when AR is received.
Activation Request Extended
The IEC-Q is requested to enter the power-up state and to start an
activation procedure by sending the wake-up signal TL. After "EQ Training"
the state "Line Active" will be entered independently of the timer T1, i.e. if
the signal SN3 has been received correctly by the LT the "Line Active" state
will be entered, even if the T1 timer has expired. Note however that if the T1
timer expires in "EQ Training" the C/I code EI3 will still be issued and should
be ignored by the control unit upstream.
Activation Request Local Loop-back
The IEC-Q is requested to operate an analog loop-back (close to the
U-interface) and to start the start-up sequence by sending the wake-up tone
TL. This command may be issued only after the IEC-Q has been set to the
"Deactivated" state (C/I-channel code DI issued on DOUT) and has to be
issued continuously as long as loop-back is requested.
Deactivation Confirmation
This command enables transition from the Deactivated state to the Awake
state, if an awake tone has been detected. If this command is not given in
the transmission to the Awake state is disabled. However awake tones from
downstream will still be recognized and latched. For more information refer
also to Note 42, page 153.
In the U-Only activation mode the DC command can be used by the control
unit on the LT side to achieve transmission transparency when the terminal
148
Operational Description
Data Sheet 01.99
PEB 2091
PEF 2091