CX28344 Conexant, CX28344 Datasheet - Page 67

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

CX28342/3/4/6/8 Data Sheet
2.1.2.3
28348-DSH-001-B
E3-G.751 Mode
When E3-G.751 mode is set, two alarms can be generated: RAI (yellow alarm) and
AIS according to the G.751 standard.
RAI (Yellow Alarm)
Bit 11 set 1 of E3-G.751 frame structure is the A-bit and used to transmit the remote
alarm indication (RAI). RAI alarm is defined as transmitting 1 on A-bit.
Each of the framers has an option to insert the A-bit:
!
!
!
!
If automatic RAI is enabled (by setting AutoRAI in Transmit Overhead Insertion 1
Control register to 1), as long as LOS condition or OOF are detected at the receiver,
the transmitter automatically inserts 1 at the transmitted A-bit (starting and stopping
at first opportunity). When LOS and OOF conditions are no longer detected, the
transmitter sets the transmitted A-bit to 0 (no RAI alarm). In the automatic RAI mode
the transmitter side sends automatic RAI as long as OOFAlm or LOSAlm bits at the
Maintenance Status register are set. Detection of LOS and OOF are specified at the
alarm detection section.
Forcing a RAI alarm can also be done by setting TxAlm [1] to 1. As long as TxAlm
[1] is set to 1, A-bit contains 1, regardless of other A-bits sourcing settings.
AIS
E3 AIS is defined as unframed all-1s.
In E3 mode, transmission of AIS is enabled by setting TxAlm0 high. When AIS is
enabled, the framer ignores the inserted data and Overhead bit settings and transmits
an all-1s code as long as TxAlm0 bit is set to 1. Start of AIS transmission and
termination in E3 is immediate with the setting of TxAlm0.
With payload (when the method of overhead insertion is all with the data stream)
From TEXT pin
Automatically generate it
Force RAI alarm sending by a control register
Mindspeed Technologies™
Functional Description
2
-
21