What an E3 contains

An E3 carries 480 DS0s, per ITU-T G.702 and ITU-T G.704.

E3 → 16 × E1 → 30 × E0 → 1 × DS0

Down to DS0

16 × E1 ITU-T G.70216 E1s, which is 4 E2s × 4 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 × E2 ITU-T G.702Four E2s.