FCO DFMZA-F002 (DAS), Composite link probs with flow control

This Field Change Order (FCO DFMZA-F002) addresses several issues affecting DFMZA-BA/BB and 70-20999-01/02 units at revision C1 or lower. The identified problems include composite link flow control causing MUXserver/DECmux II to hang, incorrect CRC error counts, intermittent reboots due to DC power cable issues, and potential signal shorts to chassis ground.

The solution is to replace the affected DECmux II units with a REV D1 unit. Two replacement kits are available: EQ-01578-02 for 120 Volt AC operation and EQ-01578-03 for 240 Volt AC operation, each containing an updated DECmux II assembly and the FCO document. A co-requisite for this FCO is the installation of DSRZA-F002 (Rev. D1) on the attached MUXserver 100 and MUXserver 100 software at V2.3.

Installation involves obtaining customer permission, recording existing system and port parameters, powering off and removing the old DECmux II, installing the new REV D1 unit from the appropriate kit, verifying self-test, restoring system parameters, and finally returning the unit to the Network Manager for reconfiguration and re-initialization of operational parameters. A small flat blade screwdriver is required, and the estimated Mean Time To Install (MTTI) is 1.5 hours.