Is there a way to reset an AP7931 without using the serial port?

[Anonymous user]

I have an AP7931 and I'm trying to connect to it but the serial port seems unresponsive. It pretty much seems completely dead. Nothing I type results in a prompt. The only activity I've seen from it is if I connect to the serial port and then power up the AP7931. When it powers up, ONE DOT comes across the serial port. That's all I've seen.

I've been able to figure out the IP Address of the unit and it will respond to a ping, and respond to an http request on port 8080 with a 403 Forbidden response. The unit does not seem to accept a telnet or ssh connection. Even if it could, I don't have the credentials for the unit.

Is there anyway to give this thing a HARD reset? Is it bricked?

Any help is appreciated!

[BillP]

Hi Jeremy,

As far as resetting this model to defaults, the only way is through the serial port.

To confirm, you're using the APC RJ-12 to DB-9 cable (part # 940-0144 printed on DB-9 end) @ 9600 baud rate? (Or maybe you have others you know that work properly and evidence just points to this one unit being a problem)

What LEDs do you see on the display and what is their color? There are two LEDs on the RJ-45 jack, one has a checkmark and X (status) and I presume this is solid green? And link LED says 10/100 next to it so maybe this is flashing orange for 100mbps?

What about the load LEDs above the 7-segment display where current value shows?

Is the PDU outputting power normally? 

[Anonymous user]

LEDs: Each receptacle's green LED is on. I tested one and it seems to be powered just fine. On the RJ-45 the status light is solid green. Link is flashing orange. Status light flashes alternating colors on reset. All that stuff looks like it's supposed to. 7 segment display is lit. Nothing plugged in, so it shows a 0. I plugged in a hair dryer to test because I knew it wouldn't be a trivial draw, and it showed several amps of draw. The dot LED labeled 'Line' next to it is green. (I'm kind of color blind so it COULD be yellow, but I don't think so. It's the same color as all the other green lights).

Cables... I have a 940-0144 that came with the PDU accessory kit. This thing seems like it's alive (responds to pings via ethernet), but with all services shut off and a disabled serial port.

[BillP]

Hmm. OK, yes all of that sounds good. There is no way to disable the serial port (via a setting anyway). You can disable pretty much everything else. Only other thing would be to make sure you don't have SCROLL LOCK on by accident. Maybe try a different terminal program? Also, flow control should be set to off, stop bits 1, parity none - just wanted to make sure one of those didn't accidentally get changed.

Are you using a USB to serial adapter that could be interfering somehow? Very well just could be a problem with the serial port too. I am just talking through all of the things I am used to or have encountered myself.

[Anonymous user]

Just following up here... I DID have success in getting access via the serial port on this unit. To document what I did...

Basically, it all came down to the fact that my terminal software was defaulting to passing CR+LF when I hit enter. I changed it to just CR, and voila! I start seeing the prompt. I'm surprised that I wouldn't see the prompt when using CR+LF... but that is what finally made it work for me.

[BillP · Accepted solution]

Thanks for sharing your findings as I know I made a note of it and it could help someone else!