page 3
10/2018
TEDIA
®
USB converters UC-232 and UC-485
page 4
10/2018
TEDIA
®
USB converters UC-232 and UC-485
3. UC-485 Converter
TEDIA UC-485 converter is a tiny isolated converter intended for expanding the number of RS-485 COM
ports using the PC USB peripheral.
The RS-485 circuits are isolated from the USB port; modern circuits providing high tolerance against
inductive overvoltage have been used for the design.
The converters provide two LED indicators; TXD indicates the data are being transmitted (from PC to
the RS-485), while RXD indicates the data are being received (from the RS-485 to PC).
Connecting of the RS-485 signals (DATA-, DATA+, GND) is realised by a wire terminal allowing easy
making and quick attaching of the line wires. See Fig. 2 or the converter label for the wiring diagram.
The converter provides the termination impedance which can be activated by the DIP switch (both
segments ON; if both segments are OFF, the termination impedance is disconnected), see Fig. 2.
Fig. 2. UC-485 Internal Circuit Schematics.
isolation
Tab. 2. UC-485 Converter Specifications.
Supported signals
DATA+, DATA-
Terminating Impedance
120 Ohm, active topology
Transfer Rate
460 kBd max.
Isolation Voltage
2.5 kV
RMS
ESD Protection
8 kV (IEC 61000-4-2, contact discharge)
15 kV (IEC 61000-4-2, air discharge)
Additional Protection
TVS 5V/200W (20A, 8/20 µs pulse, IEC 61000-4-5)
LED Indicators
TXD a RXD
Supply Voltage
5 V (supplied from the PC USB port)
Current consumption
350 mA max.
Dimensions
66 x 20 x 12 mm (inc. terminals and USB connector)
Terminals
1 mm
2
USB controller
FT232R, USB 2.0 Full Speed compatible
