The datasheet of the EM406A says:

"
Electrical level TTL level, Output voltage level: 0V ~ 2.85V
RS-232 level
"

What does this exactly mean?

This is what I inferred from the above lines:

The TX/RX lines transmit signals with
0v ==>LOW
2.85v ==>HIGH

this first has to be converted to the 0v-5v logic level (for which, i designed a level shifter)
->and then given to the serial port using a logic level converter( such as MAX-232))
->and then displayed on the hyper terminal running at 4800 baud.


But while communicating to a microcontroller, is the logic level converter(MAX232) necessary? Currently, I am simply using the 2.85v to 5v circuit and then giving the TX of the 8051 to the RX of the GPS module and visa versa. Am I right?

Regards
Sonia Sanghvi
P.S Here's the link to the datasheet again:
http://www.sparkfun.com/datasheets/GPS/EM-406A_User_Manual.PDF