thanku Mr Michael Karas and everyone else
but i Mr Michael i actually have to send the data to a CLI device. which i think doesnt requires square waves. i actually want to send (CLI)data to a particular bit of a port where a CLI device is connected ... and which takes in data as ;....



Data signal frequencies

The mark (logical 1) frequency shall be 1200 +/- 100 Hz and the space (logical 0) frequency shall be 2200 +/- 100 Hz.

Data signal-off level

The maximum power in the frequency bands from 1100 Hz to 1300 Hz and 2100 Hz to 2300 Hz in the signal-off state shall not exceed -50 dBm.

Data transmission rate
The data transmission rate shall be 1200 +/- 50 bits per second.



so can i do it with a microcontroller ????

i b very gratefull if u could plz help me out with this