![](http://datasheet.mmic.net.cn/330000/PSF21911_datasheet_16445374/PSF21911_69.png)
PSB 21911
PSF 21911
U-Transceiver
Semiconductor Group
69
11.97
2.5.7.4
Outputs of the U-Transceiver
Signals and indications are issued on IOM-2 (C/I-indications) and on the U-interface
(predefined U-signals).
C/I Indications
AI
Activation Indication
The U-transceiver has established transparency of transmission in the
direction IOM to U-interface. In an NT1, the S-transceiver is requested to send
INFO4 and to achieve transparency of transmission in the direction IOM to S/
T-interface.
AIL
Activation Indication Loop-back
The U-transceiver has detected ACT = 1 while loop-back 2 is still established.
In an NT1, the S-transceiver is requested to send INFO4 (if a transparent loop-
back 2 is to be implemented) and to keep loop-back 2 active.
AR
Activation Request
The U-receiver has synchronized on the incoming signal. In an NT1, the S-
transceiver is requested to start the activation procedure on the S/T-interface
by sending INFO2.
ARL
Activation Request Loop-back
The U-transceiver has detected a loop-back 2 command in the EOC-channel
and has established transparency of transmission in the direction IOM to U-
interface. In an NT1, the S-transceiver is requested to send INFO2 (if a
transparent loop-back 2 is to be implemented) and to operate loop-back 2.
DC
Deactivation Confirmation
Idle code on the IOM-2 interface. The U-transceiver stays in the power-down
mode unless an activation procedure has been started from the LT-side. The
U-interface may be activated but the S/T-interface has to remain deactivated.
DR
Deactivation Request
The U-transceiver has detected a deactivation request command from the LT-
side for a complete deactivation or a S/T only deactivation. In an NT1, the S-
transceiver is requested to start the deactivation procedure on the S/T-
interface by sending INFO0.
EI1
Error Indication 1
The U-transceiver has entered a failure condition caused by loss of framing on
the U-interface or expiry of timer T1.