FAQs on USB (Universal Serial Bus)
Q: My computer has only a 9 pin serial port but my
new device (Printer, Camera, etc.) has only USB Connections.
Do you have a converter that can be used to connect them?
A: You need a USB Host Connection to support
the USB device. A USB Host Connection cannot be supported
by RS-232 Serial port connections since the USB host port
requires a microprocessor and software to drive it. In theory,
a USB Serial Server is possible, but not practical since special
drivers would still be needed on the computer for each device.
Q: My new laptop computer has only a USB port, but
I need to connect a 9 pin serial device. How can I connect
to it? What can I use?
A: Use a USB to RS-232 Converter. (such
as USO9ML2
or 232USB9M) This will
work well with recent software written for Windows. Older
DOS based software which doesn't use the Windows drivers may
need to use a PCMCIA card. (SSP-100,
DSP-100, QSP-100).
Q: What USB to serial converters are recommended
for use with Windows XP?
A: The USO9ML2
USB to RS-232 and USOPTL4
& USPTL4 USB to RS-422/485
Converters all have XP compatible drivers.
Q: Does a USB to RS-232 Converter work both ways?
A: The RS-232 connections provide standard
inputs and outputs that match a regular 9 pin or 25 pin serial
port. A USB converter must connect to a USB Host port. The
USB connector (Type A Male) only fits upstream device connectors
(Type A Female) such as a Host port. USB Device (slave) devices
which don't have a cable attached have a downstream (Type
B Female) connector.
A: What are USB Type A or B Male and Female Connectors?
Q: Type A are Upstream connectors toward
Host computer. Type B are Downstream connectors toward Devices.
The USB connectors & cables carry power, ground and a differential
pair of data lines. USB connectors are designed so you can
only make proper connections between the USB Host and USB
(slave) Devices. Two USB devices can only communicate with
the Host, not directly with each other.
 
 
Q: Can I use USB devices with NT 4.0?
A: Microsoft does not support USB in NT
4.0 To use USB with the EDGEPORT series of USB to series products,
Inside Out Networks provides a USB software Stack that is
installed with their USB drivers.
Q: How do I access a USB Serial Port Converter?
A: The same as any other Windows based Com
port. Software that runs in Windows using standard Windows
drivers will be able to access the port as another Com number.
Windows supports Com1 to Com255, usually a USB device will
become the next available com port. This can be Com3, Com4,
Com5, Com6 or higher. Properly designed Windows based applications
will be able to access any port number unless limited to Com1
to Com16 or less.
Q: How does your USB to RS-422/RS-485 Converter show
up on my system?
A: After the drivers are installed, it looks
like another Com port with a different number. If you install
more units by connecting them, each unit will be assigned
the next available Com number. The new com port shows up in
the Control Panel, System, Device Manager, Ports as a Com
number. The USOPTL4
and USPTL4 converters
support Receive and Transmit signals using RS-422 operation
or 2-wire or 4-wire RS-485 mode using Automatic Send Data
Transmitter/Receiver Control.
Q: How compatible are USB based Serial Ports? What
should I be aware of?
A: Applications written for Windows 98/SE/ME/XP
or 2000 which use the standard Windows drivers will work properly.
Older software written for DOS or which only works with Com1
to Com4 in Windows 95/98/SE/Me may have problems. This includes
many PLC utilities and software attempting RS-485 transmitter
control using RTS. Automatic Send Data Control is recommended
for RS-485 use in Windows. Contact the software manufacturer
to inquire if their application works with USB & PCI based
Com ports. If not, you will need to use a motherboard or ISA
bus com port set to a legacy address and IRQ.
Q: How many USB based Serial Ports can I add?
A: If you have enough computer resources,
one USB port can support up to 127 devices using USB Hubs
to obtain additional connections. In the EDGEPORT product
line a single converter can provide 1, 2, 4, 8 or 16 serial
ports.
Q: Where can I get more information about USB?
A: At the USB website: http://www.USB.org
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