CAN232 is a very small blue dongle that plugs into any PC COM Port, or any other RS232 port
in an embedded system and gives an instant CAN connectivity. This means it can be treated
by software as a standard COM Port (serial RS232 port) which eliminates the need for any
extra drivers. Sending and receiving can be done in standard ASCII format.

CANUSB is a very small dongle that plugs into any PC USB Port and gives an instant
CAN connectivity. This means it can be treated by software as a standard COM Port
(serial RS232 port) which eliminates the need for any extra drivers or by installing a
direct driver DLL for faster communications and higher CAN busloads.
Sending and receiving can be done in standard ASCII format.
Read more at www.canusb.com