Fibersystem 21-219 - General description; Functional; IEEE C37.94

General description
Functional
The 21-219, Fiberoptic IEEE C37.94 - G.703 E1 converter is intended to extend
distance and galvanic isolate the teleprotection equipment for substations connection
to telecom network.
IEEE C37.94
The standard “IEEE C37.94-2002, IEEE Standard for N times 64 Kilobit per
Second Optical Fiber Interfaces between Teleprotection and Multiplexer Equipment”
describes a fiberoptic intra-substation communication links between teleprotection
equipment and multiplexers.
125µs 250µs 375µs 500µs
(256 bit frame)
0hgfedcb 0 0 0 1a 111
( 16 bits )
Header (sync)
1/ss/rr/qq/p 0 1 0 1p 010
( 48 bits )
Overhead
01
……...
D1
( 192 bits )
Channel Data (payload)
……...
/D1 D2 /D2 D3 /D3 D4 /D4 D96 /D96
The bit c in “Header” is used for “Yellow Alarm”. (Every other frame).
Bits p,q,r and s in “Overhead” form a HEX-value indicating the number of timeslots
used for data.
0.0.0.1 for N=1
0.0.1.0 for N=2
….
1.1.0.0 for N=12 , (0CH).
12 timeslots, (1 timeslot has 8bits
Î 12x8bits=96bits. With complement bits Î
2x96=192 bits). Data bits in not used timeslots are set to 1.
4