Modemulator User Guide
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27
of
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then send call-progress messages to the legacy application
software that mimic those of a dial-up
modem. If the
answering
Modemulator is configured to auto-answer or if the application
software
issues an answer command, the connection will complete, which emulates the behavior of dial-up
modems.
If the
answering
Modemulator does not auto-answer or manually answer, the connection will
time-out, which emulates the behavior of dial-up modems.
If the
answering
Modemulator has a cellular connection already in-progress with another
Modemulator, the current connection will not be interrupted and the
originating
Modemulator will
report
NO DIALTONE
or
BUSY
or
NO CARRIER
.
The following diagram illustrates a simplified peer-to-peer legacy system using two Modemulators and
peer-to-peer cellular service.
Single-Ended Operation
chapter in this guide to verify that one Modemulator is operating properly.
System Architecture
A legacy M2M
host
site (Headquarters, Operations Center, Transaction Processor) is the destination of
data being transferred from all of the
remote
sites. This
host
site has application hardware and software
that interfaces with the Internet to accept an IP connection and transfer the data.
The legacy M2M
remote
sites are the sources of data being transferred to the
host
site. Each
remote
site has application hardware and software that normally interfaces with a serial dial-up modem used to
transfer the data.
Modemulators can replace the dial-up modems at all or some of the
remote
sites. The Terminal port of
the Modemulator at each
remote
site connects to a serial port of the
remote
application hardware that
would normally connect to a serial dial-up modem.
