In the light of the morning, answers come:
http://www.sparkfun.com/tutorials/215
It looks like the MFC is using an RS232 standard but the Arduino is using TTL serial standard. These two protocols differ in two main ways:
1. TTL is high for 1 and low for 0, whereas RS232 is the opposite
2. The voltages on TTL and RS232 can be wildly different
However, I happen to know that the voltages one the two devices are ok, so for me its just a matter of inverting the signal. I can in principle just get a signal inverter, however, I will also order a RS232 to Serial converter:
RS232 Shifter SMD
http://www.sparkfun.com/tutorials/215
It looks like the MFC is using an RS232 standard but the Arduino is using TTL serial standard. These two protocols differ in two main ways:
1. TTL is high for 1 and low for 0, whereas RS232 is the opposite
2. The voltages on TTL and RS232 can be wildly different
However, I happen to know that the voltages one the two devices are ok, so for me its just a matter of inverting the signal. I can in principle just get a signal inverter, however, I will also order a RS232 to Serial converter:
RS232 Shifter SMD
http://www.sparkfun.com/products/449
Update, I added a simple voltage inverter circuit in front of the receive on the Arduino and MAGIC, it now reads the signals from the MFC just fine! Now all that is left is sending...
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