Alternative call waiting service with Perl
THE LISTENER
If you can’t get through to your home number, a script can check the line status and send a signal to you via the Web to tell you when the line is free.
You’re trying to call home, but somebody is hogging the line. Of course, you could always ask your telco to enable call waiting. The service lets marathon phone users know that a call is waiting by beeping every couple of seconds. On the other hand, the service costs money, and the beep can get on your nerves. This is what prompted me to buy a small phone amplifier, and put together a handy application. The Smart Phone Recorder Control grabs the signal off the phone line and feeds it to the sound card in my Linux computer. Linux can access the signal via the /dev/dsp device, and the Perl Audio::DSP module from CPAN will read it. The script uses a couple of heuristic tricks to determine whether the line is busy, and if so, it keeps on trying until the line is free, before notifying the user via a hidden CGI script on a website.
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
US / Canada
UK / Australia
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Arch Linux Available for Windows Subsystem for Linux
If you've ever wanted to use a rolling release distribution with WSL, now's your chance.
-
System76 Releases COSMIC Alpha 7
With scores of bug fixes and a really cool workspaces feature, COSMIC is looking to soon migrate from alpha to beta.
-
OpenMandriva Lx 6.0 Available for Installation
The latest release of OpenMandriva has arrived with a new kernel, an updated Plasma desktop, and a server edition.
-
TrueNAS 25.04 Arrives with Thousands of Changes
One of the most popular Linux-based NAS solutions has rolled out the latest edition, based on Ubuntu 25.04.
-
Fedora 42 Available with Two New Spins
The latest release from the Fedora Project includes the usual updates, a new kernel, an official KDE Plasma spin, and a new System76 spin.
-
So Long, ArcoLinux
The ArcoLinux distribution is the latest Linux distribution to shut down.
-
What Open Source Pros Look for in a Job Role
Learn what professionals in technical and non-technical roles say is most important when seeking a new position.
-
Asahi Linux Runs into Issues with M4 Support
Due to Apple Silicon changes, the Asahi Linux project is at odds with adding support for the M4 chips.
-
Plasma 6.3.4 Now Available
Although not a major release, Plasma 6.3.4 does fix some bugs and offer a subtle change for the Plasma sidebar.
-
Linux Kernel 6.15 First Release Candidate Now Available
Linux Torvalds has announced that the release candidate for the final release of the Linux 6.15 series is now available.