Cisco offers a variety of connectivity, expansion and upgrade modules and cards to accommodate the customer specific needs. Cisco's components are easily and inexpensively upgradeable as customer requirements change.The various optional capabilities of Cisco MC3810 series concentrators are supported by replaceable functional modules, which are mounted in specific mounting locations in the chassis.This Multiflex Trunk Module (MFT) provides interface to a E1 trunk via BNC connectors and contains an integrated, long-haul CSU/DSU.