System information

Home automation
Asterisk is still too much of an über-geek’s tool to be able to serve in the average home,
but with no more than average Linux and Asterisk skills, the following things become
plausible:
Monitoring the kids
Parents who want to check up on the babysitter (or the kids home alone) could
dial an extension context protected by a password. Once authenticated, a two-way
audio connection would be created to all the IP phones in the house, allowing Mom
and Dad to listen for trouble. Creepy? Yes. But an interesting concept nonetheless.
Locking down your phones
Going out for the night? Don’t want the babysitter tying up the phone? No problem!
A simple tweak to the dialplan, and the only calls that can be made are to 911, your
cell phone, and the pizza parlor. Any other call attempt will get the recording “We
are paying you to babysit our kids, not make personal calls.”
Pretty evil, huh?
Controlling the alarm system
You get a call while on vacation from your mom who wants to borrow some cook-
ing utensils. She forgot her key, and is standing in front of the house shivering.
Piece of cake: a call to your Asterisk system, a quick digit string into the context
you created for the purpose, and your alarm system is instructed to disable the
alarm for 15 minutes. Mom better get her stuff and get out quick, though, or the
cops’ll be showing up!
Managing teenagers’ calls
How about allocating a specific phone-time limit to your teenagers? To use the
phone, they have to enter their access codes. They can earn extra minutes by doing
chores, scoring all As, dumping that annoying bum with the bad haircut—you get
the idea. Once they’ve used up their minutes…click…you get your phone back.
Incoming calls can be managed as well, via caller ID. “Donny, this is Suzy’s father.
She is no longer interested in seeing you, as she has decided to raise her standards
a bit. Also, you should consider getting a haircut.”
The Future of Asterisk
We’ve come to love the Internet, both because it is so rich in content and inexpensive
and, perhaps more importantly, because it allows us to define how we communicate.
As its ability to carry richer forms of media advances, we’ll find ourselves using it more
and more. Once Internet voice delivers quality that rivals (or betters) the capabilities
of the PSTN, the phone company had better look for another line of business. The
PSTN will cease to exist; all its complexity will be absorbed into the Internet, as just
one more technology. As with most of the rest of the Internet, open source technologies
will lead this transformation.
586 | Chapter 27: Asterisk: A Future for Telephony