Phone and Voice Node
This node is actually two small boxes. One houses the text to
converter, and the other the various phone interfaces.
Text to Speech Converter
This unit was purchased from a commercialy company called RC systems. I
found their add in the back of Circuit Cellar Ink. I wanted a unit that
did not have a prerecorded vocabulary like the DigiTalker DT1050 from
Semiconductor. The RC Systems unit can accept a serial or parallel (PC
printer) port type of interface. I decided to wire up the parallel port
version because it allows the most flexibility. The speech quality is
good, but one can definitely tell that it is synthetic. The box has a
output, and the output is also routed to one of the unused pins on the
parallel port connector. Another pin on this port also controls an
relay that switches the destination of the spoken sound. This allows
phone interface to inject the sound into the phone line, or allow it to
be broadcast by speaker.
The unit was about $150 from RC
in Everett, WA.
The Phone Interface
The phone interface is capable of the following:
- Generating DTMF (touch tone) signals
- Decoding DTMF signals
- Decoding Caller ID signals
- Taking the phone off hook (seize the line)
- Injecting sound from the voice node into the phone line
- Detect incoming call rings
- Decoding network messages to send to text to voice box
I used the Caller ID decoder kit from the (now defunct) ITU
to receive the name and number of the caller. The DTMF generation uses
the PWM output of the PIC to produce the dual tone waveform, and the
decoding is done by a dedicated chip.
With these functions, the central controller can give the
of options and decode which selection he/she desires. This will make
control possible of the system by phone. In this manner, the entire
can be controlled and configured using any phone in the world.
- 6/13/03 - Updated information from RC systems (still
Tech (defunct). The phone node has continued to function in
manner. More functions have been added such as speaking the
log out loud if a user is sending commands via the phone.
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