CX28344 Conexant, CX28344 Datasheet - Page 65

• Manufacturer Part Number: CX28344
• Description: (CX2834x) Dual / Triple / Quad / Hex / Octal - Enhanced DS3 / E3 Framer
• Manufacturer: Conexant

CX28342/3/4/6/8 Data Sheet
2.1.2.2
28348-DSH-001-B
DS3 Mode
In DS3 M13/M23 and C-bit parity modes RAI, AIS, and IDLE alarm signals can be
generated on the outgoing DS3 stream by setting the TxAlm1 and TxAlm0 bit pair in
the Mode (i) Control register for each framer individually.
alarms. In C-bit parity mode, a FEBE alarm is also generated. The various alarms are
described in the following paragraphs.
Table 2-3. DS3 Mode Alarm Signal Setting
RAI (Yellow Alarm)
The yellow alarm is contained in the X1 and X2 bits (by setting them to 0). The
Yellow alarm is controlled by TxAlm[1:0] regardless of X-bits sourcing settings.
Setting the TxAlm bit pair to 01 sends the Yellow alarm. X1 and X2 bits are sent as 0
as long as TxAlm bit pair is set to 01. The start and termination of RAI occur in the
next frame after setting of TxAlm [1:0] bits.
AIS
The AIS signal has a valid M-frame alignment channel, a valid M-subframe
alignment channel and valid P-bits, all C-bits are set to 0 regardless of DS3 framing
mode (M13/M23 or C-bit parity), both X-bits set to 1, and the payload set to a 1010...
pattern starting with 10 after each Overhead bit.
Generation and transmission of the AIS signal is enabled by setting the TxAlm [1,0]
bit pair to 11. It continues as long as TxAlm [1,0] bits are set to 11. When TxAlm
[1,0] bit pair is set to 11, the transmit line output is replaced with the DS3 AIS pattern.
The pattern is generated internally regardless of the inserted data and Overhead bits
insertion method from the system side, which is ignored by the framer.
NOTE:
TxAlm0
0
0
1
1
Mindspeed Technologies™
When the transmitter starts generating the AIS alarm, it continues keeping the old M-
frame’s synchronization. The start and termination of AIS generation are frame
aligned (AIS transmission initiates with the beginning of the next frame after setting
TxAlm [1,0] bit pair to 11 and terminates at the beginning of the next frame after
setting TxAlm [1,0] bit pair to other than 11).
Bits
TxAlm1
0
1
0
1
Table 2-3
Type Alarm
RAI (Yellow)
Normal
IDLE
AIS
summarizes the
Functional Description
2
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