USB to RS-232 interface converter


USB to RS-232 interface converter is intended for conversion from USB interface (USB 1.1, USB 2.0) into two independent RS-232 interfaces in duplex and half-duplex modes of data exchange.

USB to RS-232 interface converter  Click on image to enlarge


USB interface

Parameter Value
Quantity of channels 1
Quantity of ports 2
Version of interface USB 1.1, USB 2.0
Connector type USBA-1J (Type «А») (male)
Signals DATA+, DATA-

RS-232 interface

Parameter Value
Quantity of channels 2
Connector type DB-9M (male)
Data exchange mode half-duplex, duplex
Connection scheme 9-wire
Signals TxD, RxD, RTS, CTS, DTR, DSR, DCD, RI, GND
Baud rates from 2 400 to 115 200 bit/sec
Data formats 8-N-1, 8-E-1, 8-O-1
Flow control no, XON/XOFF, CTS/RTS
Word length 7 or 8 bits
Stop bits 1 or 1.5
Control bit none, even, odd

Power supply

Parameter Value
Source USB interface
Voltage 5 V DC
Current consumption 100 mA (not more)

Area of application

Parameter Value
Area of application internal
Temperature range 0... + 55 deg. C
Exploitation mode round-the-clock


Parameter Value
Dimensions 93 х 52 х 16 mm (not more)
Case material ABS plastic
Weight 0.1 kg (not more)

RS-232 interface cable characteristics

Parameter Value
Type 24AWG (5 category)
Active resistance 7 Ohm (100 meters of single wire)
Capacity 0,005 uF (100 meters of twisted pair)
Wave resistance 120 Ohm

Cable length and baud rate at data exchange on RS-232 interface

Baud rate (bits/sec) Distance, m
230 400 15
115 200 25
57 600 50
38 400 80
19 200 120
14 400 160
9 600 200
1 200 – 4 800 200


1. Power supply.

Power supply is made from host-controller (power unit of personal computer) or from USB-hub with internal power supply +5 V.

2. Connection.

Connection is done to host-controller (system case of personal computer) or to USB-hub through cable USB-A, mounted into case of the converter. Peripheral devices with RS-232 interfaces is connected through DB-9F connectors (female).

3. Interaction of the personal computer with USB to RS-232 interface converter.

Physical USB-port of the converter – channel of USB interface, which is connected to computer or hub. Virtual USB-ports of the converter are created in Windows OS after connection of the physical USB-port to computer and installation of the converter drivers: “USB Serial Converter A“ and “USB Serial Converter B”.

Physical COM-ports of the converter – channels of RS-232 interface, having names COM1 and COM2, to which external peripheral devices are connected. Virtual COM-ports of the converter are created in Windows OS after installation of the converter drivers. These program virtual ports correspond to physical COM-ports of the converter, which Windows OS gives names “COMx” with numbers from 1 to 256.

As a result with virtual COM-ports of the converter a software application can work as with general COM-ports and request to virtual COM from the application leads to control over physical port port of the converter.

4. FTDI FT4232H drivers.

Operational systems for FTDI drivers:

Support for WinCE

FTDI drivers are available for Windows CE 4.2-5.2, 6.0/7.0 and 2013.

All drivers can be downloaded from the web-site of the manufacturer of FT4232H chip:


USB to RS-232 interface converter   USB to RS-232 interface converter
Order code: USB-COM-001