![](http://datasheet.mmic.net.cn/330000/PM4351_datasheet_16444271/PM4351_217.png)
STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
PROPRIETARY AND CONFIDENTIAL
193
Register 055H: T1 XBAS Alarm Transmit
Bit
Type
Function
Default
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Unused
Unused
Unused
Unused
Unused
Unused
XYEL
XAIS
X
X
X
X
X
X
0
0
R/W
R/W
When the E1/T1B bit of the Global Configuration register is a logic 1, this register
is held reset.
This register controls the transmission of Yellow or AIS alarm.
XYEL
The XYEL bit enables the XBAS to generate a Yellow alarm in the appropriate
framing format. When XYEL is set to logic 1, XBAS is enabled to set bit 2 of
each channel to logic 0 for SF and SLC96 formats, the Y-bit to logic 0 for
T1DM format, and XBAS is enabled to transmit repetitions of
1111111100000000 (the Yellow Alarm BOC) on the FDL for ESF format. If the
JPN bit of the T1-XBAS Configuration register is a logic 1 and the SF format
is selected, the framing bit of frame 12 is forced to logic 1 when a Yellow
alarm is enabled. When XYEL is set to logic 0, XBAS is disabled from
generating the Yellow alarm.
XAIS:
The XAIS bit enables the XBAS to generate an unframed all-ones AIS alarm.
When XAIS is set to logic 1, the XBAS bipolar outputs are forced to pulse
alternately, creating an all-ones signal. When XAIS is set to logic 0, the
XBAS bipolar outputs operate normally.