SECTION 4D - HAYES COMPATIBLE MODEM INTERFACE
Once the programming mode is exited, the Model 16 will attempt modem
initialization by sending the initialization string. It will retry every 5
seconds until it succeeds or until it sees a local access request (break).
MODEM OPERATION
After the Model 16 has been programmed for modem operation and the modem
plugged into the serial port, the Model 16 will initialize the modem and
the system will then be ready for operation. It may take up to 5 seconds
for the Model 16 to send the initialization string to the modem. When it
does, the tx/rx activity lamps on the modem will flicker momentarily.
To initiate a call to the Model 16, you call it up as would be done for any
normal modem communications. If you are not familiar with this process,
consult the manual for your communications software. The modem connected to
the Model 16 will detect ringing on the telephone line and will auto-answer
the line after the programmed number of rings have been seen (factory
default is 1 ring).
After the modem answers a new incoming call and establishes a connection
with the calling device, it will send an appropriate response code to the
Model 16 informing it that a connection has been made and at what baud
rate. The Model 16 will respond by adjusting its baud rate if needed. The
Model 16 then switches out of the modem protocol mode and into a user mode
where it
will respond to the modem caller the same as if a local connection
had been made. To the caller, once the modem connection has been,
established, programming and/or paging from the Model 16 is identical to
local operation.
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C A U T I O N
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Always exit the programming mode completely before commanding the calling
modem to hang up the phone line. Many modems will transmit a burst of
random characters when the calling modem hangs up. Should this happen while
the Model 16 is in the programming mode, you could end up with a corrupted
database!
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4D-2
