Manual G Code not sending in Repetier Host

Hi,
I have recently setup and successfully printed several objects. However, I have never been able to send manual G Code from Repetier Host. I can type them and hit enter and they disappear, I can scroll through the list of the codes I tried to send however nothing goes through. I don't see them populate in the bottom screen either.

Could this be a Baud Rate issue. I'm using a Mac and when I first set everything up it showed a Rate of 57600. So that's what I used in my Firmware and Repetier Host. After some reading I came across some vague responses stating that a lower Rate could case code to not transfer over. My prints seem ok though. Also Ive read that the Baud rate of my Mac doesn't necessarily have to match my Firmware and Host settings for things to work right. Did I understand that correctly? Also, I tried registering at the Repetier forum and it didnt have a submit button so i couldnt do it..

Specifically Im trying to run the M303 command to autotune my hotend thermister as Im having big (7-8 degree) swings.

Any help would be huge!

Thanks
Bryan

Up top for the night crew

Figured it out. For those who are new to this like me, G code must be typed with CAPITAL letters (M303 not m303), at least on Mac. It may seem obvious to some but it wasnt to me until I stumbled randomly across this info typing in all sorts of searchs about g code not being sent to the printer manually.

Well done and thanks for posting the solution.
Just the sort of small thing that can really frustrate you.