Specification :

WireSpan 620 is a cost-effective, single-port fractional E1/ Ethernet
access unit. The fractional E1 service makes unused time slots on
long-range E1 trunks available for other users.
WireSpan 620 provides a interface conversion between E1 and
Ethernet. The available data rates are integer multiples of 64 Kbps; the
multiples range is 1 through 32, corresponding to a maximum of 2048
Kbps. The user’ s payload data is packed into time slot of an E1 ( CEPT
2.048 Mbps) data stream, for transmission over public or private E1
networks.