The Cisco 7600 Series Ethernet Services 20G (ES20) line cards are a multiple-fabric, fixed-port Ethernet line card for the Cisco 7600 Series Routers that are capable of 20 Gbps of traffic forwarding using a fixed port interface design. The two versions of the Cisco 7600 Series Ethernet Services 20G line card are:

2-port version: 7600-ES20-10G.
20-port version: 7600-ES20-GE.
The difference between the two versions are the link interface daughter cards that accept small form-factor pluggable (SFP or XFP) optical transceivers. Additionally, each of the two versions has a packet engine daughter card and a control processor daughter card.