APC UPS won't talk to me

Discussion in 'Apple' started by notme, Jul 23, 2009.

  1. notme

    notme Guest

    [Re-posted with new subject and more appropriate NG's)

    Using a USB-to-Serial adapter to connect a laptop to APC UPS' RS232 serial

    No signs of communication from the UPS. The laptop's OS has an
    auto-recognition feature that enables built-in power-down options if/when the
    UPS communicates its presence.

    Loop-back test of the serial adapter confirms data is going out and coming
    back, being displayed in a terminal program. (Local echo turned off.)

    Serial cable (between adapter & UPS) is the correct APC p/n (with unique pin
    assignments) for this application and model of UPS. Confirmed this with APC
    tech support.

    Tried power-cycling the UPS, and connecting the serial cable before & after.
    No joy.

    What options are left? This is a new (well, New, Old Stock) UPS and has not
    seen any use before I powered it up last week.


    Mac PowerBook; OS X 10.4.11
    APC Backup-Pro 650 (model BP650S); APC serial cable #940-0095B
    No-name USB-Serial adapter w/1.2.1r2 Prolific OS X driver

    notme, Jul 23, 2009
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  2. http://www.apc.com/resource/include/techspec_index.cfm?base_sku=BP650S&CF

    says this product is discontinued. It also says there's a DB-9 RS-232
    port for signaling a power outage. Usually these sorts of signals tell
    the attached system to "power down gracefully" with the aid of software
    running on the system. Solaris used to use Powerchute with APC backups
    to do this sort of shutdown. According to the Wikipedia page, the
    RS-232 pin-outs are non-standard and proprietary to APC. APC makes a
    version of Powerchute for MacOS X:


    If you're up to "rolling your own", then that leaves you to reverse
    engineer the interface, then write a program that, when installed, runs
    on bootup (rather than just when someone logs in) and listens to the
    USB-Serial adapter for a signal that the power has gone out, then runs a
    graceful shutdown script.

    Seems like a lot to go through for a laptop. If this was going on a
    server system, I could see where this would be nice hackware project.
    Don't know what APC would do to you if they found you reverse
    engineering their product, but that's your problem.

    Have fun.
    Michael Vilain, Jul 23, 2009
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  3. notme

    notme Guest

    Yes, I know. "Discontinued" does not mean obsolete. New models are introduced
    every month so as to keep that cash rollin' in. The "old" models still
    provide a service. (In my case for $0.)
    According to e-mail correspondence with APC tech support, there is no
    Powerchute version compatible with the BP650S UPS model. They recommend using
    the built-in UPS monitoring features in Mac OS X.
    Not worth it, if that's the answer.

    I hope someone chimes in this discussion that they experienced this issue and
    found a way to make it work with the built-in OS's UPS monitoring features...

    notme, Jul 23, 2009
  4. notme

    notme Guest

    So you know the cable is OK via APC support .AND. that loopback works OK.
    If data is going out and coming in, that means the USB driver works. Yes?
    It's not a stand-alone app. It's part of the System Preferences of Mac OS X.

    And Googling a bit, I've seen no evidence that the UPS monitoring feature has
    been an issue with other models of UPS.

    So, I suspect it's a non-standard spec of the APC UPS communication spec for
    this model. Worst case.

    notme, Jul 23, 2009
  5. That's what the Wikipedia article on Powerchute said. The serial
    pinouts are non-standard and the signals coming out are proprietary.

    Start by buying a break-out box to test the signals in the RS-232
    interface to see what they do when the power is cut. Then see what the
    USB converter does with that. If it doesn't see anything, you'll have
    to craft your own converter.

    Given you're lack of maker-ethic (e.g. you won't "figure it out for
    yourself"), my guess is you'll have to either pay someone else to do it
    or wait until someone with identical UPS and Macintosh get it running or
    retire the unit to paperweight duty until your wife says to clean up
    your mess. Either way, unless you figure it out and get it working,
    it's not going to be doing much of anything right now.
    Michael Vilain, Jul 23, 2009
  6. notme

    Nobody Guest

    UPSes don't normally speak serial. More often, they simply connect two
    pins together, treating the serial port as a general-purpose I/O port.
    This won't work with a USB-to-serial converter, as there is no serial data
    to convert.
    Nobody, Jul 23, 2009
  7. FAIK APC UPS communication should be started by sending a question mark to

    petrus bitbyter
    petrus bitbyter, Jul 23, 2009
  8. APC used to have an adapter cable. My guess is that a "standard"
    USB-to-RS-232 cable is not likely to work.

    As another person said, I don't see the point for a notebook, even a desktop
    replacement. I assume the Mac has some system for automatic shutdown as the
    batteries are drained. (Windows does.) So, simply set it and the computer
    will shut down gracefully is power is lost.
    William Sommerwerck, Jul 23, 2009
  9. notme

    VAXman- Guest

    try: Y

    But the BackUPS don't use APC's Smart protocol.

    VAXman- A Bored Certified VMS Kernel Mode Hacker VAXman(at)TMESIS(dot)ORG


    "Well my son, life is like a beanstalk, isn't it?"
    VAXman- , Jul 23, 2009
  10. notme

    notme Guest

    If I had an APC Smart-UPS with both RS232 and a Smart Slot, the serial port
    on the Smart-UPS would have a better chance of working with my USB-serial

    notme, Jul 23, 2009
  11. APC used to have an adapter cable. My guess is that a "standard"
    Well, they did it to me. I was told I needed a special cable, but it didn't
    work. Turned out that when I directly connected the standard cable to the
    computer (running W2K), the machine immediately recognized the UPC.
    William Sommerwerck, Jul 23, 2009
  12. notme

    notme Guest

    For troubleshooting purposes, what settings should the terminal program use?
    - VT100 or PC-ANSI?
    - High bit stripped?
    - Drop DTR on exit?
    - Auto line-feed?

    notme, Jul 23, 2009
  13. notme

    notme Guest

    I tried both (with & without special cable). No joy.

    notme, Jul 23, 2009
  14. notme

    notme Guest

    APC Tech Support's final solution: Plug the UPS into a PC and see if it
    recognizes it.

    Being a Mac guy, don't know much about the Win world. Is there UPS
    communication & recognition features built into Win XP? Or do I need to have
    APC management software installed?

    notme, Jul 23, 2009
  15. Being a Mac guy, don't know much about the Win world. Is there
    If it's in W2K, it should also be in XP.

    The supplied cable has a J connector on one end, USB on the other. A few
    seconds after both ends are plugged in, the OS recognizes that a UPS
    (strictly speaking, an SPS) is connected and opens the Power Options
    Properties tab. Couldn't be simpler.

    There is no need to use APC's PowerChute, unless it has a specific feature
    no in the Windows OS.
    William Sommerwerck, Jul 23, 2009
  16. To add in: Many of the basic APC UPS's don't use true serial
    communications. They just use some of the control lines to signify power
    out, low battery, and to signal the UPS to do a shutdown. I don't know
    if it will work correctly through a USB-to-serial adapter.

    My work computer has a BP650M with a self-made cable. It's just a
    standard 9-pin serial cable, but the UPS end is slightly rewired, and I
    think there is also a resistor. It's just using the stock Win2K support.
    Andrew Rossmann, Jul 23, 2009
  17. notme

    notme Guest

    This has been said a few times here. Until I get a breakout box and look at a
    few of the lines on that connector to see if it's actually data or just
    pulling lines high or low, I won't know.
    I know that APC says that a standard serial cable won't work. I'm using their
    p/n cable that came with the UPS.

    Thanks for your input.
    notme, Jul 23, 2009
  18. I recommend you check out:


    I tried to get APC:s software to run on a Solaris x86 system, but gave
    up. apcupsd works fine, even through a prolific based usb-serial

    I haven't tried it on MacOS though.

    I have an APC Smart UPS 700, which speaks serial, not some status port
    wiggle. It does require a APC specific cable though.

    The link above contains references to simple commands that can be
    issued through a terminal emulator to verify that the communication
    Thomas Tornblom, Jul 23, 2009
  19. First: I was mistaken about the question mark. You should send a Y.

    You should use a normal ANSI terminal set to: 2400,n,8,1

    APC is known for using non-standard cables. The one I saw had the next

    PC(DE9F) UPS(DE9M)

    But there sure are other ones depending on the UPS-type. This one is for the
    APC Smart UPSs.
    No need to say there's no hardware handshake in this one.

    But... Does your UPS talk RS232 anyway? I seem to remember that BackupPro
    types are rather dumb things that only do some signaling i.e. using pin 2 to
    tell the UPS is on battery. Guess on the PC side this should be considered a
    "break" and that's all.

    petrus bitbyter
    petrus bitbyter, Jul 23, 2009
  20. notme

    notme Guest

    Thanks for that. A great resource for APC owners who want to hack the device.

    The commands you speak of are commands sent through the apcupsd daemon, not
    thorough a terminal program. Building the daemon for OS X and installing it
    is a (to me) monumental task.

    But I think joining the support mailing list could prove helpful.

    Thanks again.
    notme, Jul 24, 2009
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