Module 2 channels(2 transmit and 2 receive), RS232 and V.28-speeds up to 230Kb. Operates from a single 3.3v or 5v Power source, ESD protected in excess of +/- 15Kv. on all I/O lines, 4 LEDs(2 for transmit, 2 for receive), Pre-installed headers for transceiver lines, Pre-installed headers for +3.3v or +5v and Ground.