Asterisk VoIP calls causing PPP to drop on ADSL modems

The internet FTW.

I’ve been having this odd problem since I got my Asterisk box back up and running in that whenever a call came in and hung up I’d lose internet connectivity for a few seconds.

I tracked it down to the router dropping the PPP connection, which initially made me think that the polarity reversal indicating the call had hung up was causing the modem to b0rk, perhaps due to the distance between the phone socket and the modem, or my dodgy cat5 cabling, or something.

Turns out it was none of the above.  EDIT:  Bit hasty there.  Hasn’t fixed it al all.

This post:,43733.msg209081.html#msg209081

points to exactly my problem. I disabled the DDoS protection and no more dropped internet connections. I don’t worry about DDoS attacks too much, so for now I’m going to leave it off.

UPDATE:  None of the above actually worked.  In the end it turned out the modem had simply broken.  The NV RAM wasn’t remembering the config after a proper reboot and it was generally broken.  So I replaced the whole thing with a new DrayTek modem.  The old one did pretty well, it worked perfectly for about 3 years non-stop.

Search hints:

DrayTek VoIP Asterisk dropping ADSL PPP drop DDoS SIP

SMSq No call scheduled as already sending

In order to remind myself:

I kept getting this error when trying to send an SMS;

No call scheduled as already sending

It seems SMSq or Asterisk is quite picky about who sends the SMS. If I tired to send an SMS as myself it would fail, and then clog up /var/spool/asterisk/sms/motx with undead SMSes.

If I run smsq as the same user as Asterisk is running as it works (once you’ve deleted all the crap out of motx directory.

Just need to work out why now.

Getting NUT to talk to LiebertPSP UPS

I got hold of a couple of LiebertPSP UPSes and connected to my servers.  They’re perfectly good for what I need them for, namely stopping my servers having the rug pulled out from underneath them with no notice if there is a power cut.

They don’t appear to have advanced functions like switching off the load independently of the supply which means you can’t power down the servers and then have the UPS switch them back on again once the power is restored and the battery has had a chance to charge, but I can live without that sort of thing.

I assumed that something somewhere would support these, and for the most part NUT does a bang up job.  It’s a bit advanced for my needs but most of the work has already been done.  In NUT the LiebertPSP is sort-of-supported by the Belkin USB driver with a few notable exceptions:

  • The Online/On Battery indication doesn’t work
  • The numeric values don’t work for things like Output Voltage

The numbers I can live without but the Online / On Battery is really rather important.

So I’ve cobbled together a new sub-driver using the tools supplied with Nut.  It’s far from complete but it does fix most of the annoying problems.


You’ll need to download the Nut source and put the .c and .h files in the above tarball in to the drivers directory, then you’ll need to apply this patch in the drivers directory to get the new driver included in the build and to stop the native Belkin driver from claiming the ID of the LiebertPSP:


Then recompile Nut.

If everything works you should see a bit more info from your UPS:

battery.type: PbAc
device.mfr: Emerson Network Power
device.model: LiebertPSP
device.type: ups usbhid-ups
driver.parameter.bus: 004
driver.parameter.pollfreq: 30
driver.parameter.pollinterval: 2
driver.parameter.port: auto
driver.version: 2.4.3-2519M LiebertPSP HID 0.1
driver.version.internal: 0.35
ups.input.frequency: 50.0
ups.input.voltage: 243
ups.mfr: Emerson Network Power
ups.model: LiebertPSP
ups.output.percentload: 54
ups.output.voltage: 240
ups.powersummary.capacitygranularity1: 1
ups.powersummary.capacitygranularity2: 1
ups.powersummary.capacitymode: 2
ups.powersummary.configvoltage: 12.0
ups.powersummary.designcapacity: 100
ups.powersummary.fullchargecapacity: 100
ups.powersummary.imanufacturer: 19
ups.powersummary.ioeminformation: 19
ups.powersummary.iproduct: 1
ups.powersummary.presentstatus.batterypresent: 1
ups.powersummary.presentstatus.belowremainingcapacitylimit: 0
ups.powersummary.presentstatus.charging: 1
ups.powersummary.presentstatus.discharging: 0
ups.powersummary.presentstatus.needreplacement: 0
ups.powersummary.presentstatus.shutdownimminent: 0
ups.powersummary.rechargeable: 1
ups.powersummary.remainingcapacity: 100
ups.powersummary.remainingcapacitylimit: 38
ups.powersummary.voltage: 14
ups.powersummary.warningcapacitylimit: 38
ups.productid: 0001
ups.status: OL
ups.vendorid: 10af

Search hints:

Vendor ID: 0x10af

Product ID: 0x0001

Posted by / October 6, 2010 / Posted in linux