Owner's manual

Technical Description
OMG-USB-485-1 Page 8
Technical Description
The OMG-USB-485-1: utilizes a USB UART. This chip features programmable
baud rate, data format, 128 byte Dual Port TX Buffer, and 384 byte Dual Port RX
Buffer. The RS-530/422/485 transceiver supports data rates up to 921.6K baud..
Features
• Hot-Pluggable device that doesn’t require opening the case
• No system resources are required (i.e. I/O ports or IRQ’s)
• LED status indicators for “USB Enabled”, “TD”, and “RD”
Connector Pin Assignments (DB25 Male)
The OMG-USB-485-1 complies with the EIA-530 pin out with the following
signals supported
Signal Name Pin # Mode
GND Ground 7
RDB RX+ Receive Positive 16 Input
RDA RX- Receive Negative 3 Input
CTSB CTS+ Clear To Send Positive 13 Input
CTSA CTS- Clear To Send Negative 5 Input
DSRB DSR+ Data Set Ready Positive 22 Input
DSRA DSR- Data Set Ready Negative 6 Input
DCDB DCD+ Data Carrier Detect Positive 10 Input
DCDA DCD- Data Carrier Detect Negative 8 Input
TDB TX+ Transmit Positive 14 Output
TDA TX- Transmit Negative 2 Output
RTSB RTS+ Request To Send Positive 19 Output
RTSA RTS- Request To Send Negative 4 Output
DTRB DTR+ Data Terminal. Ready Positive 23 Output
DTRA DTR- Data Terminal Ready Negative 20 Output