In addition to the simple telephone devices covered previously
there are also other less common devices which are specialised
to perform a particular function, yet still connect and behave
as a simple telephone device.
Some more common examples are:
||These monitor the status of an alarm system,
and when triggered or at a pre-set time will dial a pre-set
number and deliver a report or message on the status of
the system being monitored.
|Fixed Dial Telephones
||These simple telephones have
a pre-programmed memory or memories, which are dialled
when the user picks up the phone and/or presses
a button. These stored numbers are the only destinations
that can be called, as there is normally no separate dialling
pad. Uses include emergency telephones and those to free
call a specific service such as a taxi company.