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
-
Latest Cinnamon Desktop Releases with a Bold New Look
Just in time for the holidays, the developer of the Cinnamon desktop has shipped a new release to help spice up your eggnog with new features and a new look.
-
Armbian 24.11 Released with Expanded Hardware Support
If you've been waiting for Armbian to support OrangePi 5 Max and Radxa ROCK 5B+, the wait is over.
-
SUSE Renames Several Products for Better Name Recognition
SUSE has been a very powerful player in the European market, but it knows it must branch out to gain serious traction. Will a name change do the trick?
-
ESET Discovers New Linux Malware
WolfsBane is an all-in-one malware that has hit the Linux operating system and includes a dropper, a launcher, and a backdoor.
-
New Linux Kernel Patch Allows Forcing a CPU Mitigation
Even when CPU mitigations can consume precious CPU cycles, it might not be a bad idea to allow users to enable them, even if your machine isn't vulnerable.
-
Red Hat Enterprise Linux 9.5 Released
Notify your friends, loved ones, and colleagues that the latest version of RHEL is available with plenty of enhancements.
-
Linux Sees Massive Performance Increase from a Single Line of Code
With one line of code, Intel was able to increase the performance of the Linux kernel by 4,000 percent.
-
Fedora KDE Approved as an Official Spin
If you prefer the Plasma desktop environment and the Fedora distribution, you're in luck because there's now an official spin that is listed on the same level as the Fedora Workstation edition.
-
New Steam Client Ups the Ante for Linux
The latest release from Steam has some pretty cool tricks up its sleeve.
-
Gnome OS Transitioning Toward a General-Purpose Distro
If you're looking for the perfectly vanilla take on the Gnome desktop, Gnome OS might be for you.