On Sat, 13 Jan 2024 21:32:44 +0000 (UTC) phoebus phoebus <frphoe...@yahoo.fr> wrote:
> I have a client workstation with a proprietary terminal emulator > running on Windows. This PC is connected to a POS printer via a COM > serial port. The client workstation along with the printer and other > connected devices, forms the client-side of our Point of Sale (POS) > system. … > The printer model is a Thermal Line Dot Printing type and it supports > the ESC/POS command system, created by Epson, which provides > efficient and functional commands for communication with the printer. > For more information on ESC/POS, please refer to this site: > https://download4.epson.biz/sec_pubs/pos/reference_en/escpos/index.html This article was very helpful. > Our objective is to explore open-source solutions for this > configuration as we aim to replace the proprietary software. I take it that by "the proprietary software" you mean the proprietary terminal emulator running on the client PC. One thing you might be able to do quickly is establish an SSH tunnel between the PC and the server, then route the proprietary terminal emulator telnet traffic through the tunnel. That, at least, will get you a more secure connection between the PC and the server. If I understand things correctly, the server sends all sorts of information to the proprietary terminal emulator. Most of that gets displayed on the emulator. But, given one VT escape code, the emulator sends the subsequent data off to the printer, until it gets the other VT escape code. The printer may then return a response. If that understanding is correct, I suggest you grab an existing open source terminal program that supports VT escape codes: 1) Modify how it handles those two escape codes. 2) Modify it to listen to the printer for responses, encode those appropriately, and ship them to the server. I haven't worked with VT escape sequences in decades. If I recall correctly, some escape sequences cause the terminal to send information back to the server. In that case, you may need to synchronize return information from the printer with other return information. -- Does anybody read signatures any more? https://charlescurley.com https://charlescurley.com/blog/
