I replaced my old APC SmartUPS 620 with an updated model. I had lost the serial cable that allows you to communicate with the UPS via a computer for the old unit. The new unit came with the serial cable and for a while I was looking for the correct pin out so I could build a cable myself. So I wanted to get the pin out documented. The cable is a male to female DB9 cable. Well I got my voltmeter and using the continuity setting I mapped the pinout. It would not be difficult to create this cable. Many of the cables DB9 serial cables I had laying around were female to female and it was hard finding a male end. Hopefully this will help others out there that need this cable and don’t want to pay $30 for it.
UPDATE: I have updated the diagram based on the comments I got on this post. Apparently I counted the male pins incorrectly so I made the correction. Thanks for your feedback.
July 3rd, 2009 at 12:52 am
Hi, you have the SmartUPS cable slightly wrong. The picture is correct, but you have counted the pins on the male connector incorrectly. The correct table should be:
Fem Male
2 2
3 1
5 9
Cheers,
November 12th, 2009 at 11:26 pm
Mr Ball (posted on 7/3/2009) is correct you should correct the db9 male side pin numbers. Other wise nice diagram!
Thanks…
March 31st, 2011 at 7:36 am
On some other sites it says that you have to add a 10k ohm resistor too..
whats that all about?
aint that required?
June 20th, 2011 at 6:37 am
I’ve got with my APC 620 a cable imprinted 940-0024c with your pin assignments, just to confirm. Checked for R of 10K, but no resistors found.
June 22nd, 2011 at 8:07 am
No
There are 2 diffrent comunication options: via a software that monitorises the ups or via 3 signals.
This cable here is for the 1) part.
For the other type,check: http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q102711& (this is quite useless,since it is very rudimentar amd the apc soft offers much more options)