IDT82P2288 Integrated Device Technology, Inc., IDT82P2288 Datasheet - Page 58

• Manufacturer Part Number: IDT82P2288
• Description: 8 Channel T1/J1/E1 Transceiver
• Manufacturer: Integrated Device Technology, Inc.

IDT82P2288
3.11.2.2
and FISU (refer to Figure 14). Their opening flag and closing flag are
discarded, the extracted SS7 data stream is compared with the standard
SS7 packet. If the value of the 6-bit length indication is equal to ‘0’, the
SS7 packet is FISU; if it is equal to ‘1’ or ‘2’, the SS7 packet is LSSU; if it
is more than ‘2’, the SS7 packet is MSU.
into blocks. Each block (except the last block) has 32 bytes. The block
will be pushed into a FIFO with one-byte overhead until any of the fol-
lowing invalid packet conditions occurs:
than 5 bytes (including the FCS, excluding the flags);
of octets;
the closing flag is not 5 bytes (including the FCS, excluding the flags);
the closing flag is not 6 or 7 bytes (including the FCS, excluding the
flags);
Functional Description
'01111110'
'01111110'
one byte
one byte
Flag
Flag
In SS7 mode, there are three kinds of signaling units - MSU, LSSU
After the stuffed zero (the zero following five consecutive ’One’s) is
The data stream between the opening flag and the FCS are divided
- A packet with error FCS;
- The data between the opening flag and the closing flag is less
- The extracted SS7 packet does not consist of an integral number
- A 7F (Hex) abort sequence is received;
- If the SS7 packet is FISU, the data between the opening flag and
- If the SS7 packet is LSSU, the data between the opening flag and
SS7 Mode
two bytes
two bytes
FCS
FCS
Signaling Field
n bytes (n>1)
one or two bytes
Status
'01111110'
one byte
Flag
Figure 14. Standard SS7 Packet
Link Status Signaling Unit (LSSU)
Message Signaling Unit (MSU)
Fill In Signaling Unit (FISU)
Information
two bytes
one byte
Service
FCS
Octet
47
two
bits
two
bits
two
bits
both 7E (Hex). The closing flag may also serve as the opening flag of
the next HDLC packet.
the closing flag is less than 8 bytes or more than 271 bytes (including
the FCS, excluding the flags).
discarded, but the one-byte overhead will still be written into the FIFO.
The overhead consists of the M[2:0] bits and the length indication bits as
shown in Figure 13. In FISU/LSSU, if the FISU/LSSU filter is set by the
FISUFIL/LSSUFIL bit respectively, the current FISU/LSSU will be dis-
carded if it is the same with the previous FISU/LSSU. In this condition,
no data and overhead of the current FISU/LSSU will be written into the
FIFO.
DAT[7:0] bits. When the overhead is read from the FIFO, it will be indi-
cated by the PACK bit. When all valid SS7 blocks are pushed into the
FIFO or all the blocks are read from the FIFO, it will be indicated by the
EMP bit.
When there are conditions meeting the interrupt sources, the corre-
sponding Interrupt Indication bit will be set to ‘1’ and the Interrupt Indica-
tion bit will be cleared by writing a ‘1’. A ‘1’ in the Interrupt Indication bit
OCTAL T1/E1/J1 LONG HAUL / SHORT HAUL TRANSCEIVER
Indication
Indication
( = 1 or 2 )
Indication
Length
Length
Length
- If the SS7 packet is MSU, the data between the opening flag and
If any of the above conditions is detected, the current block will be
The FIFO depth is 128 bytes. The FIFO is accessed by the
The interrupt sources in this block are summarized in the Table 30.
six bits
six bits
six bits
( > 2 )
( = 0 )
Indication
Indication
Indication
Forward
Forward
Forward
one bit
one bit
one bit
Bit
Bit
Bit
Sequence
Sequence
Sequence
Forward
Forward
Forward
Number
Number
Number
seven
seven
seven
bits
bits
bits
Backward
Indication
Backward
Indication
Backward
Indication
one bit
one bit
one bit
Bit
Bit
Bit
Backward
Sequence
Backward
Sequence
Backward
Sequence
Number
Number
Number
seven
seven
seven
bits
bits
bits
March 22, 2004
'01111110'
'01111110'
'01111110'
one byte
one byte
one byte
Flag
Flag
Flag