Is there a pause in the data stream, or is the Axon CONSTANTLY sending, i.e as soon as one packet is sent the next is on its way? The UART is not transmitting at exactly the correct baud rate, just as close as it can get. If there is no pause, the amount of error builds up, and complete gibberish is spewed from the other end.
Try adding a delay of say, 50ms after it has sent a packet of data, for the UART to recover.
-HyperNerd