What an E4 contains

An E4 carries 1,920 DS0s, per ITU-T G.702 and ITU-T G.704.

E4 → 64 × E1 → 30 × E0 → 1 × DS0

Down to DS0

64 × E1 ITU-T G.70264 E1s, which is 4 E3s × 16 E1s.
1. 30 × E0 ITU-T G.70430 voice channels in 32 timeslots. TS0 is framing and TS16 is channel-associated signalling.
  1. 1 × DS0 ITU-T G.702E0 and DS0 are each one 64 kbit/s PCM channel.
4 × E3 ITU-T G.702Four E3s.