Toll fraud is on the rise. Just last month, one of my clients faced a $1,200 bill due to fraudulent activity on their phone system. Somebody hacked into their system by using a default user name and password for a conference phone and made hundreds of minutes of international calls.
Toll fraud is more common today because VoIP phone systems are more popular. VoIP systems can be hacked because they are connected to the Internet. The costs associated with fraudulent activity add up fast.
Digital phone systems can be hacked, too, but it's much harder and thus rarely happens.