The Adtran OPTI-MX module provides a DS3 or EC1 tributary payload from the OPTI-MX system. The signal is made available through one of the in and out BNC pairs on the OPTI-MX chassis.
Adtran 1184502L11 Data Networking Overview
The 1-Port OC-3 Multiplexer Module terminates the OC-3 fiber circuit(s) to feed the OPTI-6100 chassis. It operates only in Terminal mode. It converts the optical signal into STS-3 digital electrical signals for distribution through the backplane wiring to the tributary modules.