Result: standard mapping
How many E1s are in an E4?
An E4 carries 64 E1s, per ITU-T G.702.
64
E1s in an E4
Working
E4 → 64 × E1
- 64 × E1 in each E4 ITU-T G.70264 E1s, which is 4 E3s × 16 E1s.
- 64 E1s
Leftover capacity
8.192 Mbit/s of each E4 line rate (139.264 Mbit/s) sits outside 64 × 2.048 Mbit/s of E1 line rate (131.072 Mbit/s). That remainder is overhead, fixed stuff or justification. It is not another whole tributary.
By bit rate only
Dividing the line rates gives 68, which floors to 68 E1s by bit rate only. The standard mapping is 64. Use the mapping.