The Two-port STM-1/OC-3 Channelized E1/T1 line card provides E1/DS1 aggregation for the Cisco
12000 series Internet Router. The Two-port STM-1/OC-3 Channelized E1/T1 line card interfaces with
the 12000 series Internet Router switch fabric and provides two OC-3/STM-1 duplex SC single-mode
intermediate-reach optical interfaces.

When configured for operation in a Synchronous Digital Hierarchy (SDH) environment, each STM-1
port is capable of supporting channelization into either 63 independent E1s through VC-12 ETSI
mapping, or 84 J1 (Japanese T1 equivalent) channels through VC-11 ANSI mapping.

When configured for operation in a Synchronous Optical Network (SONET) environment, each OC-3
port is capable of supporting channelization into 84 independent DS1 (VT1.5 mapping or CT3 mapping
into STS-1) channels.

Fractional E1 and individual 64 kbps channels can also be configured, up to the limit of 105 channel
definitions per STM-1 (35 per TUG-3). Fractional T1 and individual DS0 channels can also be
configured, up to the limit of 35 channel definitions per STS-1 (210 per line card).

Each Two-port STM-1/OC-3 Channelized E1/T1 line card supports up to 126 E1s when configured for
SDH operation, 168 DS1 connections when configured for SONET operation, or any combination of 64
kbps/DS0, fractional E1/T1, or E1/T1 interface definitions, up to the limit of 210 per line card.