[OT] Remote Data Acquisition Programming
A client has installed a number of site controllers linked to fuel dispensers
in distant retail sites to provide automated fuelling services. Communication
between the site controllers and a central front end processor (FEP) is via
telephone links with modems attached to RS232 interfaces at both ends.
I have a strong desire to implement a new, open and robust front end processor
using Debian GNU/Linux primarily for automated remote data acquisition or
data download/transfer from the controller to the FEP.
So far, I've managed to get hold of the non-standard protocol specifications
for communication between the FEP and site controller. The communication
scheme is basically the exchange of well formatted message blocks eg. STX -
Start of text, , EOT, ACK - Acknowledgment, NAK, ENQ etc. with both binary
and ASCII values.
My dilemma is on how to send these messages from within a C program and over a
telephone link. For example, what interface should I look at in this case -
the modem or serial port? I have read Serial port and Modem HOWTOs and also
Serial programming for POSIX operating systems but still can't deduce the
best way to apprroach the problem. Are there any APIs in Linux for
programming the modem/serial port or is making low level i/o system calls the
only way out?
Grateful for any guidance on the best way to proceed.
Thanks and regards,