I'm trying to get apcupsd to work with my Ups (APC Back-UPS 700VA) with my server running Debian 9 stretch but can't connect to ups and get this when I run:

rene@odroidxu4-share:~$ sudo apcaccess status
[sudo] password for rene:
APC      : 001,018,0453
DATE     : 2019-01-13 18:44:10 +0000
HOSTNAME : odroidxu4-share
VERSION  : 3.14.14 (31 May 2016) debian
UPSNAME  : smartups750
CABLE    : USB Cable
UPSMODE  : Stand Alone
STARTTIME: 2019-01-13 18:44:00 +0000
MBATTCHG : 5 Percent
MINTIMEL : 3 Minutes
MAXTIME  : 0 Seconds
TONBATT  : 0 Seconds
CUMONBATT: 0 Seconds
STATFLAG : 0x05000100
END APC  : 2019-01-13 19:53:54 +0000

The problem is:

STATUS: COMMLOST - (No connection to UPS)

Despite I can see it's connected with:

rene@odroidxu4-share:~$ lsusb
Bus 006 Device 002: ID 0bda:8153 Realtek Semiconductor Corp.
Bus 006 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 002: ID 152d:0578 JMicron Technology Corp. / JMicron USA Technology Corp.
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 002: ID 051d:0002 American Power Conversion Uninterruptible Power Supply
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

(Bus 002 Device 002: ID 051d:0002 American Power Conversion Uninterruptible Power Supply)

Output of conf file:

sudo nano /etc/apcupsd/apcupsd.conf
## apcupsd.conf v1.1 ##
# "apcupsd" POSIX config file

# Note that the apcupsd daemon must be restarted in order for changes to
# this configuration file to become active.

# ========= General configuration parameters ============

#   Use this to give your UPS a name in log files and such. This
#   is particulary useful if you have multiple UPSes. This does not
#   set the EEPROM. It should be 8 characters or less.
UPSNAME smartups750

# UPSCABLE <cable>
#   Defines the type of cable connecting the UPS to your computer.
#   Possible generic choices for <cable> are:
#     simple, smart, ether, usb
#   Or a specific cable model number may be used:
#     940-0119A, 940-0127A, 940-0128A, 940-0020B,
#     940-0020C, 940-0023A, 940-0024B, 940-0024C,
#     940-1524C, 940-0024G, 940-0095A, 940-0095B,
#     940-0095C, 940-0625A, M-04-02-2000

# To get apcupsd to work, in addition to defining the cable
# above, you must also define a UPSTYPE, which corresponds to
# the type of UPS you have (see the Description for more details).
# You must also specify a DEVICE, sometimes referred to as a port.
# For USB UPSes, please leave the DEVICE directive blank. For
# other UPS types, you must specify an appropriate port or address.
# UPSTYPE   DEVICE           Description
# apcsmart  /dev/tty**       Newer serial character device, appropriate for 
#                            SmartUPS models using a serial cable (not USB).
# usb       <BLANK>          Most new UPSes are USB. A blank DEVICE
#                            setting enables autodetection, which is
#                            the best choice for most installations.
# net       hostname:port    Network link to a master apcupsd through apcupsd's 
#                            Network Information Server. This is used if the
#                            UPS powering your computer is connected to a 
#                            different computer for monitoring.
# snmp      hostname:port:vendor:community
#                            SNMP network link to an SNMP-enabled UPS device.
#                            Hostname is the ip address or hostname of the UPS 
#                            on the network. Vendor can be can be "APC" or 
#                            "APC_NOTRAP". "APC_NOTRAP" will disable SNMP trap 
#                            catching; you usually want "APC". Port is usually 
#                            161. Community is usually "private".
# netsnmp   hostname:port:vendor:community
#                            OBSOLETE
#                            Same as SNMP above but requires use of the 
#                            net-snmp library. Unless you have a specific need
#                            for this old driver, you should use 'snmp' instead.
# dumb      /dev/tty**       Old serial character device for use with 
#                            simple-signaling UPSes.
# pcnet     ipaddr:username:passphrase:port
#                            PowerChute Network Shutdown protocol which can be 
#                            used as an alternative to SNMP with the AP9617 
#                            family of smart slot cards. ipaddr is the IP 
#                            address of the UPS management card. username and 
#                            passphrase are the credentials for which the card 
#                            has been configured. port is the port number on 
#                            which to listen for messages from the UPS, normally 
#                            3052. If this parameter is empty or missing, the 
#                            default of 3052 will be used.
# modbus    /dev/tty**       Serial device for use with newest SmartUPS models
#                            supporting the MODBUS protocol.
# modbus    <BLANK>          Leave the DEVICE setting blank for MODBUS over USB
#                            or set to the serial number of the UPS to ensure 
#                            that apcupsd binds to that particular unit
#                            (helpful if you have more than one USB UPS).

# POLLTIME <int>
#   Interval (in seconds) at which apcupsd polls the UPS for status. This
#   setting applies both to directly-attached UPSes (UPSTYPE apcsmart, usb, 
#   dumb) and networked UPSes (UPSTYPE net, snmp). Lowering this setting
#   will improve apcupsd's responsiveness to certain events at the cost of
#   higher CPU utilization. The default of 60 is appropriate for most
#   situations.

# LOCKFILE <path to lockfile>
#   Path for device lock file. This is the directory into which the lock file
#   will be written. The directory must already exist; apcupsd will not create
#   it. The actual name of the lock file is computed from DEVICE.
#   Not used on Win32.
LOCKFILE /var/lock

# SCRIPTDIR <path to script directory>
#   Directory in which apccontrol and event scripts are located.
SCRIPTDIR /etc/apcupsd

# PWRFAILDIR <path to powerfail directory>
#   Directory in which to write the powerfail flag file. This file
#   is created when apcupsd initiates a system shutdown and is
#   checked in the OS halt scripts to determine if a killpower
#   (turning off UPS output power) is required.
PWRFAILDIR /etc/apcupsd

# NOLOGINDIR <path to nologin directory>
#   Directory in which to write the nologin file. The existence
#   of this flag file tells the OS to disallow new logins.

# ======== Configuration parameters used during power failures ==========

# The ONBATTERYDELAY is the time in seconds from when a power failure
#   is detected until we react to it with an onbattery event.
#   This means that, apccontrol will be called with the powerout argument
#   immediately when a power failure is detected.  However, the
#   onbattery argument is passed to apccontrol only after the 
#   ONBATTERYDELAY time.  If you don't want to be annoyed by short
#   powerfailures, make sure that apccontrol powerout does nothing
#   i.e. comment out the wall.

# Note: BATTERYLEVEL, MINUTES, and TIMEOUT work in conjunction, so
# the first that occurs will cause the initation of a shutdown.

# If during a power failure, the remaining battery percentage
# (as reported by the UPS) is below or equal to BATTERYLEVEL, 
# apcupsd will initiate a system shutdown.

# If during a power failure, the remaining runtime in minutes 
# (as calculated internally by the UPS) is below or equal to MINUTES,
# apcupsd, will initiate a system shutdown.

# If during a power failure, the UPS has run on batteries for TIMEOUT
# many seconds or longer, apcupsd will initiate a system shutdown.
# A value of 0 disables this timer.
#  Note, if you have a Smart UPS, you will most likely want to disable
#    this timer by setting it to zero. That way, you UPS will continue
#    on batteries until either the % charge remaing drops to or below BATTERYLEVEL,
#    or the remaining battery runtime drops to or below MINUTES.  Of course,
#    if you are testing, setting this to 60 causes a quick system shutdown
#    if you pull the power plug.   
#  If you have an older dumb UPS, you will want to set this to less than
#    the time you know you can run on batteries.

#  Time in seconds between annoying users to signoff prior to
#  system shutdown. 0 disables.

# Initial delay after power failure before warning users to get
# off the system.

# The condition which determines when users are prevented from
# logging in during a power failure.
# NOLOGON <string> [ disable | timeout | percent | minutes | always ]
NOLOGON disable

# If KILLDELAY is non-zero, apcupsd will continue running after a
# shutdown has been requested, and after the specified time in
# seconds attempt to kill the power. This is for use on systems
# where apcupsd cannot regain control after a shutdown.
# KILLDELAY <seconds>  0 disables

# ==== Configuration statements for Network Information Server ====

# NETSERVER [ on | off ] on enables, off disables the network
#  information server. If netstatus is on, a network information
#  server process will be started for serving the STATUS and
#  EVENT data over the network (used by CGI programs).

# NISIP <dotted notation ip address>
#  IP address on which NIS server will listen for incoming connections.
#  This is useful if your server is multi-homed (has more than one
#  network interface and IP address). Default value is which
#  means any incoming request will be serviced. Alternatively, you can
#  configure this setting to any specific IP address of your server and 
#  NIS will listen for connections only on that interface. Use the
#  loopback address ( to accept connections only from the
#  local machine.

# NISPORT <port> default is 3551 as registered with the IANA
#  port to use for sending STATUS and EVENTS data over the network.
#  It is not used unless NETSERVER is on. If you change this port,
#  you will need to change the corresponding value in the cgi directory
#  and rebuild the cgi programs.

# If you want the last few EVENTS to be available over the network
# by the network information server, you must define an EVENTSFILE.
EVENTSFILE /var/log/apcupsd.events

# EVENTSFILEMAX <kilobytes>
#  By default, the size of the EVENTSFILE will be not be allowed to exceed
#  10 kilobytes.  When the file grows beyond this limit, older EVENTS will
#  be removed from the beginning of the file (first in first out).  The
#  parameter EVENTSFILEMAX can be set to a different kilobyte value, or set
#  to zero to allow the EVENTSFILE to grow without limit.

# ========== Configuration statements used if sharing =============
#            a UPS with more than one machine

# Remaining items are for ShareUPS (APC expansion card) ONLY

# UPSCLASS [ standalone | shareslave | sharemaster ]
#   Normally standalone unless you share an UPS using an APC ShareUPS
#   card.
UPSCLASS standalone

# UPSMODE [ disable | share ]
#   Normally disable unless you share an UPS using an APC ShareUPS card.
UPSMODE disable

# ===== Configuration statements to control apcupsd system logging ========

# Time interval in seconds between writing the STATUS file; 0 disables

# Location of STATUS file (written to only if STATTIME is non-zero)
STATFILE /var/log/apcupsd.status

# LOGSTATS [ on | off ] on enables, off disables
# Note! This generates a lot of output, so if         
#       you turn this on, be sure that the
#       file defined in syslog.conf for LOG_NOTICE is a named pipe.
#  You probably do not want this on.

# Time interval in seconds between writing the DATA records to
#   the log file. 0 disables.

# FACILITY defines the logging facility (class) for logging to syslog. 
#          If not specified, it defaults to "daemon". This is useful 
#          if you want to separate the data logged by apcupsd from other
#          programs.

# ========== Configuration statements used in updating the UPS EPROM =========

# These statements are used only by apctest when choosing "Set EEPROM with conf

# UPS name, max 8 characters 

# Battery date - 8 characters
#BATTDATE mm/dd/yy

# Sensitivity to line voltage quality (H cause faster transfer to batteries)  
# SENSITIVITY H M L        (default = H)

# UPS delay after power return (seconds)
# WAKEUP 000 060 180 300   (default = 0)

# UPS Grace period after request to power off (seconds)
# SLEEP 020 180 300 600    (default = 20)
#SLEEP 180

# Low line voltage causing transfer to batteries
# The permitted values depend on your model as defined by last letter 
#  of FIRMWARE or APCMODEL. Some representative values are:
#    D 106 103 100 097
#    M 177 172 168 182
#    A 092 090 088 086
#    I 208 204 200 196     (default = 0 => not valid)

# High line voltage causing transfer to batteries
# The permitted values depend on your model as defined by last letter 
#  of FIRMWARE or APCMODEL. Some representative values are:
#    D 127 130 133 136
#    M 229 234 239 224
#    A 108 110 112 114
#    I 253 257 261 265     (default = 0 => not valid)

# Battery charge needed to restore power
# RETURNCHARGE 00 15 50 90 (default = 15)

# Alarm delay 
# 0 = zero delay after pwr fail, T = power fail + 30 sec, L = low battery, N = never
# BEEPSTATE 0 T L N        (default = 0)

# Low battery warning delay in minutes
# LOWBATT 02 05 07 10      (default = 02)

# UPS Output voltage when running on batteries
# The permitted values depend on your model as defined by last letter 
#  of FIRMWARE or APCMODEL. Some representative values are:
#    D 115
#    M 208
#    A 100
#    I 230 240 220 225     (default = 0 => not valid)

# Self test interval in hours 336=2 weeks, 168=1 week, ON=at power on
# SELFTEST 336 168 ON OFF  (default = 336)

Someone who has a clue why I can't connect with my Apc ups?

  • Did you edit the /etc/default/apcupsd and change ISCONFIGURED=no to yes. Then reboot with it plugged in. Jan 13, 2019 at 20:44
  • Yes Michael it is set to : Yes like you say - But stilll not working :/ Jan 13, 2019 at 20:51
  • OK, I will review my setup and get back to you. Jan 13, 2019 at 20:54
  • Thank you mabye my apc bx700ui dosent support apcupsd :/ ? Jan 13, 2019 at 21:00
  • I had that same series just before I got my new ones and it worked great. Jan 13, 2019 at 21:03

2 Answers 2


I had the same problem with COMMLOST with a USB connection, after a lot of research I found by pure hazard that with a USB connection you should change DEVICE /dev/ttys0 to DEVICE in /etc/apcupsd/apcupsd.conf with nothing after it, this way apcupsd search everywhere on the system to find the UPS and connect correctly, no more COMMLOST.

After that, restart apcupsd with:

$ sudo /etc/init.d/apcupsd restart


  • 1
    I had a similar issue after a Debian dist/full upgrade. This answer helped me. Thx
    – Kyle
    Oct 19, 2019 at 20:02
  • 1
    Correct, did help, left it blank but also had to restart the service. wiki.debian.org/apcupsd
    – luison
    Feb 17, 2020 at 19:24
  • This was the fix for my self as well. However, I needed a full reboot of the RPI(Buster). Simply restarting the service was not working. Apr 29, 2020 at 13:25
  • 1
    I had to use /etc/apcupsd/apcupsd.conf. I think you have a typo above. Dec 30, 2020 at 2:13

You can edit /etc/apcupsd/apcupsd.conf:

DEVICE /dev/ttyS0



It's worked for my Smart-UPS_1500.

  • Worked for me also. BX1000G according to apcaccess
    – LGTrader
    Dec 8, 2023 at 16:57

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