Re: Printing stops with USB to Serial adapter

From: PointZero FR ("PointZero)
Date: 02/26/05 

Date: Fri, 25 Feb 2005 19:02:40 -0500

The USB to Serial converter is branded Manhattan "USB TO SERIAL CONVERTER"
(model number 205146, UPC 766623205146), the driver identifies itself as
"Prolific USB-to-Serial Bridge" version 2.0.0.24, and I'm pretty sure it is
a flow control issue.

With flow control set to Hardware, the spooler ("Printers Folder") gets an
error "There was an error found printing the document ... to COM4:. Do you
want to retry or cancel the print job?". If I ignore this, the entire
output prints, and the message goes away.

With flow control set to Xon/Xoff or None, the output stops fairly
consistently after a byte count (~1300-1400+ characters as counted from my
app). The printer's buffer is supposedly 1kb (or somewhere close).

I have tried to configure the printer to print directly to the printer (i.e.
not spool the output so I can add some waiting), but that does not appear to
work. The output does not start until i end the print job (VB6
Printer.EndDoc). We are using VB6 SP4 on Win2k Pro SP2 (don't ask me why,
but if it makes a difference, I'd be interested...).

Output directly to the COM port tends to show up as a bunch of question
marks and blanks as if the parity or framing was off - but it is configured
according to the printer's status page (except I've tried all combinations
of stop bits and flow control - these are not printed on the printer's
status page). It is also the same settings as used for the printer driver
(when successfully printing using it).

Tore.

"Dick Grier" <dick_grierNOSPAM@msn.com> wrote in message
news:OhUzPp1GFHA.576@TK2MSFTNGP15.phx.gbl...
> Hi,
>
> This sounds like either a fault with the printer or the USB/serial driver.
> And, yes, it might be connected with a failure of flow control (either
> hardware or software). Without lots more information, it would be hard to
> speculate more.
>
> ***
>
> --
> Richard Grier (Microsoft Visual Basic MVP)
>
> See www.hardandsoftware.net for contact information.
>
> Author of Visual Basic Programmer's Guide to Serial Communications, 4th
> Edition ISBN 1-890422-28-2 (391 pages) published July 2004. See
> www.mabry.com/vbpgser4 to order.
>
>