BK650M - does not work when communication cable plugged in.

[Anonymous user]

I have a BK650M that works perfectly UNLESS I plug in the communication cable; part #940-0020B.
BUT when I connect the communication cable from the APC to the computer. The green lamp on the power switch goes out and then the battery backup does not function.

The only information remotely related to this issue is in the instruction pamphlet.
In the pamphlet it states:

"+The lamp in the Power I/0 Switch is lit whenever normal utility voltages are present at the power sockets.+"

How does plugging in the communication cable cause the voltage at the power sockets to change ?
And how does that prevent the battery from functioning ?

I really would like to solve this issue; so that during extended power outages the computer can automatically be shut down gracefully.

Thanks;
etrimmer

[Anonymous user]

I have a BK650M that works perfectly UNLESS I plug in the communication cable; part #940-0020B.
BUT when I connect the communication cable from the APC to the computer. The green lamp on the power switch goes out and then the battery backup does not function.

The only information remotely related to this issue is in the instruction pamphlet.
In the pamphlet it states:

"+The lamp in the Power I/0 Switch is lit whenever normal utility voltages are present at the power sockets.+"

How does plugging in the communication cable cause the voltage at the power sockets to change ?
And how does that prevent the battery from functioning ?

I really would like to solve this issue; so that during extended power outages the computer can automatically be shut down gracefully.

Thanks;
etrimmer

[Techie_apc]

Hi Eric,

Is this happening after attaching the serial cable to the Computer's serial port and then attaching the other end of the serial cable to the UPS's serial port? If possible, could you please try connecting another working 940-0020 cable to the UPS serial port and see if the same thing occurs? This will help us to determine if the issue lies with the cable or the UPS in question.

[Techie_apc]

This is most likely that there is an internal fault with the Serial port circuit that is causing the UPS to react the way described. Do you see any bend in the UPS serial port pins?

[Anonymous user]

Nope; no bent serial port pins.
BUT
The phrase "+*fault with the Serial port circuit*+" got me to thinking.
This PC does have an additional multi I/O card with one additional parallel port and two additional serial ports.
Although the UPS was not connected to any of those additional ports; I removed that card with those additional ports. And now the UPS functions correctly with it's cable attached.
(Although this is odd because an identical card is in another identical machine with an identical UPS. And it doesn't have an issue.)

Of course now I am missing a serial port that was used for a ppp connection.
But I can live without that ppp connection if it means this PC will shutdown gracefully during a power outage.

Thanks for your help.
--Eric

[Techie_apc · Accepted solution]

You are welcome Eric!

I am glad that you were able to find the cause of the issue.

Have a nice day!