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I'm currently attempting to see if it is possible to move a desktop based POS system to an MVC. So far using the Neodynamic Web Print Library (http://www.neodynamic.com/articles/How-to-print-raw-ESC-POS-commands-from-ASP-NET-directly-to-the-client-printer/) I've been able to utilize ESC/P commands to both print from a web page as well as send a drawer kick command.

My next goal is to see if it is at all possible to get data back from the printer. The reason I need to do this is so that I can validate things like the drawer status, slip printer in use, and paper jam etc. So far I've attempted to use the ePOS-print sdk (http://www.novopos.ch/client/EPSON/TM-T88V-i%20und%20Epson%20TM-T70-i/ePOS-Print-API/ePOS-Print_API_UM_E_RevB.pdf) but it appears that it's not possible to utilize it for any EPSON printer that is not classified as a TM-Intelligent printer. I contacted EPSON with this same question and they were very dismissive saying that I would just need to use their ASB commands but I don't see how that could possibly work when sending RAW data from a web page.

I've done a little research into signalr but i didn't find anything that i thought i would be able to use.

I'd prefer to find a way to do this without installing anything on a client's computer but if I have to install some sort of web socket in order to do this it'd be understandable.

Essentially what I need to know is

  • Is this even possible?
  • If it is possible, what do you think is the best method to pursue?

I really just need some guidance so that I can focus my research on something that might actually work. Thanks in advance for your time!

user3711258
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  • You could use web methods and call them asynchronously from JavaScript on the client side, couldn't you? – Thorsten Dittmar Jun 05 '14 at 13:24
  • I suppose I could, but the general task I've been charged with is created a POS system that won't require me to do anything client side. What i'd really like to do is just have a user be able to log into a cash receipting system online, punch in their printer id(probably an ip address), validate it with a username and pass word and bam you have a functioning web based cash receipting system. – user3711258 Jun 05 '14 at 13:30
  • A web socket is also something client side...? – Thorsten Dittmar Jun 05 '14 at 13:49
  • Good point. It looks like that's the route i'll end up having to take unfortunately. – user3711258 Jun 05 '14 at 13:52
  • I bet you misunderstand something here. Doing things client-side does *not* mean you need to install something on the client machine! It just means, that (while most of the logic is executed on the web server) some logic is also "in the HTML" sent to the client's browser - implemented using JavaScript within the HTML page. Neither for web methods nor for web sockets you need to install anything but a browser! – Thorsten Dittmar Jun 05 '14 at 14:14
  • I see what you're saying now! I'm still totally lost as to how i could query the printer for status events. – user3711258 Jun 05 '14 at 14:47
  • So the real problem is not how to do it client side, but how to do it at all - which is not clear from your question. Oh and by the way: I guess there is a printer per cash desk - how should the single web server access that printer? Network printer? – Thorsten Dittmar Jun 05 '14 at 14:48

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You have to install something client side. There are no standards for doing this. Which is the problem that Web-based POSes are wrestling with (such as Vend). The way they get around this is using printers which can talk the web themselves, something like Google cloud print. I see that Neodynamic DO install something client side, so you could ask them to enhance their software.

O'Rooney
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