USB to Serial Converters Manual
Version 2.0
Document Reference No.: CP_000032 Clearance No.: CP#022
Copyright © Connective Peripherals Pte Ltd
43
7
Troubleshooting
This section provides some advice to help if you encounter problems during installation or use of your
converter. Please check these items before contacting Connective Peripherals technical support. If you still
have problems, you can contact technical support using the contact details in section 8 on page 48.
7.1
Hardware
Cables are the most common source of problems with external devices. Please check the following:
USB Connections:
-
USB cable is properly connected at both the Computer and the Converter ends
-
Use the USB cable provided with the unit
-
Computer power is ON and computer is not in Sleep or Standby
USB Hubs:
-
If a USB Hub is used, be sure all cables are securely connected
-
It is strongly recommended to either connect the USB cable from the converter directly to a port
on the PC or via a self-pwered hub (which has its own PSU). This is recommended for all converters
but may be essential for the converters within the ES-U-xxxx-x series which are powered by the
USB port as bus-powered USB hu
bs can’t provide as much power.
-
If using a hub which can be either self- or bus-powered, use in self-powered mode and try powering
up the hub
’s power supply
before connecting it
to the PC’s USB port so that
it recognises that it is
self-powered.
-
Hubs certified by the USB-IF are recommended.
Power Connections:
-
Check that the power LED on the converter is on.
-
If your converter requires an external power supply, ensure that the power supply is securely
connected to both the power input socket on the converter and the AC power outlet.
-
If your converter has an internal power supply, ensure that the power cable is securely connected
to both the power inlet socket on the rear panel of the converter and the AC power outlet.
RS-232 Connections:
-
On converters supporting multiple protocols, check that the DIP switches are set for RS-232 mode.
-
Output signals (TXD, RTS, DTR) are connected to the respective inputs (RXD, CTS, DSR) in each
direction.
-
Signal naming conventions can vary between different manufacturers. This manual indicates
whether each signal is an input or output on the ES-U-xxxx-xx device. Check the user guide of
your RS232 device for the corresponding table and ensure that outputs form the ES-U-xxxx-xx
converter go to inputs on the attached device and vice versa.
-
Check for specific handshake requirements of your RS232 peripheral. If handshake signals are not
used, ensure the application is set to “No Hardware Handshake”, or equivalent.
Handshaking is
recommended however if supported by the attached serial device.
-
Ensure that the converter’s baud rate and parity settings match the equipment on the other end of
the cable.
-
Test the port with a loop-back connector. Connect TXD to RXD, RTS to CTS and DTR to DSR. Use
a simple terminal program to check that data is transmitted and received.
RS-485/RS-422 Connections:
