These surface mount boards are designed around the LTC490 and the LTC485 chips. They connect in-line with the PC com port to provide signal conversions from the RS232C to RS422 differential line signals.

The boards, measuring 1.4" sq. convert the TX and RX signals providing 4-wire (RS422) and 2-wire (RS485) buss implementations.

The input connection is pre-wired to take its power from the +DTR or +RTS connection and to provide feedback to the other input connections to indicate that the device is on-line.

Db9f25f.tif (32566 bytes)
Available in RS422
and RS485 format

Need something else ?
See our custom units

or the RJ45 enclosed units.

Db25f25m.tif (32566 bytes)
Available only in
RS422 format

  • Up to 115K Baud data rates!

  • Tested at 115K Baud to 1000 feet with error free operation using level 5, twisted pair, network cable, without line terminators.

  • No delayed turn-a-round time! The RS485 operates up to 115K Baud with no delays.

  • Self-powered from the RS232C PC comm port. Requires the DTR or RTS line to be set high for operation

Simple internal installation or inline cabling. Purchase the units with the optional PC bracket to mount inside the PC. Disconnect the DB 9-pin flying lead comm port connector, (or purchase the IDC flat ribbon cable extension for external to internal connections) route and attach it to the converter ...installation completed. 422bd3.jpg (1920 bytes)

cable.tif (59172 bytes)

Optional IDC cable assembly for connecting the external comport to the internally mounted converter. The flat ribbon cable easily slips in between the PC slot and PC bracket to gain access to the internal machine. 



RS485 << RS232 >> RS422
/25F /25M DB/9F /25F /25M /25F
T/RXa 2,12 2,12 2 3 TX OUT 2,5 9,12 TXa
T/RXb 3,11 3,11 3 2 RX IN 4,14 10,25 TXb


6,8,20 +DTR 3,21 11,18 RXa
VCC 17 22 1,7,8,9 4,5 +RTS 15,20 19,24 RXb
GND 7 7 5 7 GND 7 7 GND
** items temporary out of stock

ORDERING INFORMATION (minimum order 5 units)

RS422 - A DB9F input DB25M output


RS422 - B DB9F input DB25F output $25.00US 25.00CD
RS422 - C DB25F input DB25M output $25.00US 25.00CD
RS422 - D DB25F input DB25F output $25.00US 25.00CD
** RS485 - A DB9F input DB25M output $25.00US 25.00CD
** RS485 - B DB9F input DB25F output $25.00US 25.00CD
** RS485 -C DB9F input DB25M output $25.00US 25.00CD
** RS485 - D DB9F input DB25F output $25.00US 25.00CD

Optional PC bracket mounted to converter

$2.00US 2.00CD

Optional IDC DB9F to DB9M cable 16"

$10.00US 10.00CD
Coyote Kit for SII upgrade (minimum order 10 units) $43.00US each 43.00CD each 



Coyote Kit for SII

RS422/485 ORDER FORM and information package.

Send certified cheque or money order only payable to: MicroLee Technology Inc.

Canadian orders Add $8.00CD for shipping (up to 10 items)
add 6%GST Ontario residents add 8%PST
Mail to:
MicroLee Technology Inc.
28 Marlena Dr.
Scarborough, Ontario, M1E 2Z1
USA orders Add $9.00US (up to 5 items)
International orders Add $12.00US (up to 5 items)
international US money order only


Please send any inquiries to us via Email at ""

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1995 MicroLee Technology Inc. Last Updated: Nov. 12, 2007