FCO CXA16-F001, Errors on DECserver 500/550 w CXA16 installed

This Field Change Order (FCO CXA16-F001) addresses several problems occurring on DECserver 500/550 units equipped with CXA16 (M3118-YA) modules, particularly when terminals are powered off during normal operations. The issues include artificial login attempts, excessive framing errors, locked ports, excessive port overrun errors, and server slowdown due to false logins. These problems are attributed to signal cross-talk or noise from adjacent active lines when a terminal is powered down or a line is left unterminated, causing the system to misinterpret signals as login attempts. The FCO specifies that the 5180 receiver chip used in the CXA16 is involved in these incidents.

The solution requires replacing CXA16 (M3118-YA) Line Card Modules with a revision below "E2" with new modules supplied in an EQ Kit (EQ-01545-01). The document provides detailed rework instructions for field engineers, including powering down the server, carefully removing the old modules, transferring switchpack settings to the new modules, installing the new modules, restoring power, performing a self-test verification, and updating documentation. The FCO is applicable to various DSRVS-AA/AB/BA/BB (DECserver 500) and DSRVS-CA/CB/DA/DB (DECserver 550) configurations using CXA16 for RS423 applications. The estimated installation time is 0.5 to 1.0 hour.