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Yes! I'm currently working on a Windows based building access system dating back to the early 90s. Most of the codebase in MFC C++. The hardware/firmware that r
by osullivj 10y ago
Yes! I'm currently working on a Windows based building access system dating back to the early 90s. Most of the codebase in MFC C++. The hardware/firmware that runs the door controls used to talk RS232 to the Windows boxes, but now use TCP/IP. STX is used as the start char for a msg. The system is used by some very prominent govt and biz orgs.
- kosma 10y agoOne pleasant upside of such systems is that the protocols are usually so simple you can reverse engineer them in a couple evenings. I can't count the times I ended up deriving the serial protocol from some undocumented, baroque source code (or sniffer dumps) and writing a quick & dirty implementation in a few dozen lines of Python.
- osullivj 10y agoThat's exactly what I've done :) The checksum algorithm that suffixes each msg with a 2 byte check took a little bit of figuring out. I'm using tornado.tcpserver.TCPServer and tornado.iostream. Another plus is generating logs of the msg flow; useful for diagnostics, and the after the fact specs you often need with crufty old systems.