Hi,
Scope pictures:
* crop the picture and generate a smaller file size using jpeg compression
* use the "add image" button if available
* show us where the "zero" line is
* show us what signal you measured (TTL, RS232, input, output...)
* tell us what "data" you transmit. (use a constant value for debugging)
Else it is useless.
***********
MAX232:
* My datasheet shows you should use 1uF (not 100nF like you did) tantalum or ceramics capacitors with short wires.
* it produces about +10V and -10V for proper RS232 levels.
****
UART: Idle = HIGH = about 5V on TTL levels = -5 ... -10V on RS232 levels.
Klaus