S/UNI®-JET Data Sheet
Released
Figure 53 Transmit G.832 E3 Overhead
G.832 Frame Period
TOHFP
TOHCLK
TOH
FA2 EM TR
MA
NR
GC
FA2
FA1
FA1
TOHINS
54 cycles
TOHFP
TOHCLK
TOH
bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit bit
2
3
4
5
7
8
1
2
4
5
6
7
1
2
3
4
6
7
8
1
1
6
3
8
5
2
FA1 byte
FA2 byte
EM byte
TOHINS
The Transmit G.832 E3 Overhead diagram (Figure 53) shows the insertion of G.832 E3 overhead
bits using the TOH input, along with the overhead insertion enable input, TOHINS. The TOHFP
output is set to logic one once per G.832 frame period (during the first bit position of the FA1
byte). In Figure 53, the bit data sampled on TOH during each byte position while TOHINS is
logic one is inserted into the G.832 E3 overhead bits in the transmit stream. Note: If an entire byte
is to be replaced with data from the TOH stream, TOHINS must be held logic one for the duration
of that byte position. Also Note: The EM byte behaves as an error mask, that is the binary value
sampled on TOH in the EM byte location is not inserted directly into the transmit overhead but,
rather, the value is XORed with the calculated BIP-8 and inserted in the transmit overhead.
Asserting TOHINS during the “gaps” in the TOH stream has no effect.
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990267, Issue 3
308
PMC [ PMC-SIERRA, INC ]
