I see this question all over this forum but no answer has anybody knows or found the solution? I have telemetry enabled.
OK I found the answer in a different forum
http://www.supramania.com/forums/showthread.php?p=995337By Turbogate:

Now once you are done, and everything is configured properly. (See user manual for AIM MXL and Race studio, it's pretty self explanatory) All you have to do is connect to your AEM EMS with a laptop. Go to Set-up>advanced setup>Telemetry>Telemetry wizard. Double click on AEM Serial Datastream and click OK. Now you may loose connection to your AEM for a few seconds because the AEM is now in Telemetry mode. All you need to do is cycle the power (turn key off-on) so you can reconnect to your ECU. Once there, go back to Set-up>advanced setup>Telemetry>Telemetry set-up and change the Parity setting from Ignore to none (that was my issue for my original issue) then click OK, once again your laptop will loose connection to the ecu. Close out AEM pro kill the ignition to avoid connecting the serial cable to the dash while it's on, connect your AIM serial cable to the AEM serial cable and turn back on. The Dash should now be streaming the AEM selected data.
Enjoy