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Mobile HAM AID box



APRS ID BOX (AID)
At DCC I presented the idea of using the ubiquitous Caller ID boxes
as a Ham Radio universal mobile 4 line message delivery device.  
These devices are down to $12 on sale and $2 surplus.  Not only can 
they display real-time messages, but also have a 50 to 100 message 
memory.  I call this an AID box (APRS ID BOX).

The application is the dashboard of every mobile ham radio vehicle.
NO OTHER HARDWARE REQUIRED.  Just connect to your speaker.  Imagine 
the applications:  Meeting announcements, traffic/wx advisories
bulletins, Emergency calls, etc.

The beauty of it is that they use 1200 baud standard ASCII text  and
the same Bell202 tones as Packet radio.  All we need to do is 
transmit the right tones!  Any TNC with "ASCII" RTTY mode can do this.
THus it should be trivial to implement a universal LOW COST amateur
text distribution system almost overnight!

Before DCC I began experimenting.  I could easily use a BELL202
modem to receive caller ID from my phone line.  But for transmitting
to an AID box, it appears that the ID box will not receive and 
decode the text unless the ASCII tones arrive at a specific time 
after the first ring signal.  Reverse engineering the circuit reveals 
the ring rectifier does feed a pin on the PIC chip which will need to 
be spoofed; probably by the opening of the squelch.

The concept is to have a modem at each voice repeater site to 
send the tones.  It listens for special messages on a command
channel (or the APRS channel) and translates them to the AID
format.  The ideal engine to program this cross translator 
is the TAPR Pic-E which alreaady has the Bell202 modem on board.

Thus, not only APRS stations, but also ANY voice radio user can now
be efficiently informed via error-free text messages for under $5
per vehicle!

Experimenters go for it!

de WB4APR, Bob

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