@EEFF.ADF - IBM Dual Async Adapter
Dual Async Adapter 90X9229
Earlier versions use the NS16550ON chip.
Incorrect Wiring on P2
Some dual async adapters (PN 72X8529, FRU 6450347) will
cause the system to power off when a plug is inserted into the second async
port. This is caused by an incorrect connection of L2.
The system will not power up when an external device (printer,
plotter, modem, etc.) is connected to Port 2. This includes any device
that has signal and frame ground connected together. If the device does
not have the two grounds connected together, the system will power up.
However, the device will not be functional when connected to Port 2.
To determine if the device is functional, it should be tested on Port 1.
AdapterId 0EEFFh IBM Dual Async Adapter