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USB to Serial Ports Limitations RRS feed

  • Question

  • Hello team,

    The PC with only USB ports is up (see previous post) with the Prolific PL-2303 USB to Serial device. However, when the device is under presure (many invoces being printed), the device just falls shorts, as printing becomes corrupt after about 3 continued medium size orders (about 25 lines each).

    This does not happen with a regular PC with an integrated Serial port.
    - For a cashier station, then this will be a no-no, you have to put a PC with an integrated serial port.
    - For a waiter station this should work OK as the printer on those stations (at least on our software) is less stressfull.

    I think the chip on the USB is not as efficient as the one that comes with integrated in a motherboard.

    We are using the Epson TM-U950 serial printer with a 2048 bytes in buffer capacity. Printer is not the issue here, as it works well in a PC with an integrated RS-232 in the motherboard.

    This happens in Windows XP Pro, WEPOS 1.1 and PosReady 2009

    Hope this helps.
    Humberto Sequeira
    Monday, February 15, 2010 4:50 PM

Answers

  • Hello folks,

    Finally got back my serial Epson TM-U950 printer.
    I am still using the Prolific PL-2303 USB to Serial device

    - Tested at 9600 speed. It fails when printing to many lines. (3 consecutive invoices with 15 lines each).
    - Tested at 4800 speed. It fails when printing to many lines. (2 consecutive invoices with 15 lines each).

    So, for my experience, then the USB to RS-232 device is at fault when connecting to a big 2 roll printer like the Epson TM-U950.

    Use it on a waiter or bartender printer to print an invoice. Epson TM-U200/220, Samsung SRP270 or those $200 chinese printers.

    I have used, taking a risk, on a Kitchen and Bar printer, and the results have been ok, to my suprise.

    So I leave that up to you to see if this USB to RS-232 works for you.

    Humberto Sequeira
    Wednesday, March 10, 2010 4:50 AM

All replies

  • Hi Humberto,

    Not sure what we can do to help, I don't believe we have this device handy to test with.  I did a quick search on the Internet and didn't find any similar reports but I found their instruction manual.  It mentions Port Settings property page that has Bits/Second which in their screenshot appears a bit low (9600).  Is it possible to increase this on your side?  Alternatively, does decreasing help (maybe it needs to be throttled more)?

    Also, the other settings like UART and all that, I assume the defaults are set to ideal levels, but can you double check?

    Brendan
    Wednesday, February 17, 2010 12:42 AM
  • Hello Brendan,

    The max speed for the printer (device) is 9600, and that is OK for me. Let me lower it to 4800 on both ends to see if it has any effect.
    Indeed the buffers are at default, I will play around with them to see if any changes are noted.

    What I need to find out is how other members are going about connecting remote devices on new USB only machines.
    I know that some printers now come with RJ-45 ports, is that the trend to handle long distances remote printers?

    Thanks for pointing the speed, I will post the results shortly.

    Humberto Sequeira
    Friday, February 19, 2010 3:36 AM
  • Hello folks,

    Finally got back my serial Epson TM-U950 printer.
    I am still using the Prolific PL-2303 USB to Serial device

    - Tested at 9600 speed. It fails when printing to many lines. (3 consecutive invoices with 15 lines each).
    - Tested at 4800 speed. It fails when printing to many lines. (2 consecutive invoices with 15 lines each).

    So, for my experience, then the USB to RS-232 device is at fault when connecting to a big 2 roll printer like the Epson TM-U950.

    Use it on a waiter or bartender printer to print an invoice. Epson TM-U200/220, Samsung SRP270 or those $200 chinese printers.

    I have used, taking a risk, on a Kitchen and Bar printer, and the results have been ok, to my suprise.

    So I leave that up to you to see if this USB to RS-232 works for you.

    Humberto Sequeira
    Wednesday, March 10, 2010 4:50 AM