reading garbage from serial port PiTInfo

[JohnDoe]

I'm trying to get a PiTInfo v1.0 to work on a freshly installed Jessie on my Raspberry PI, but for reasons that escape me, I can only read garbage.

As far as I can tell, the console on serial port is disabled:

cat /boot/cmdline.txt 
dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait

I've got a link to ttyS0

sudo ln -s /dev/ttyAMA0 /dev/ttyS0

I've set the serial port:

stty 1200 cs7 evenp cstopb -igncr -inlcr -brkint -icrnl -opost -isig -icanon -iexten -F /dev/ttyAMA0

and yet what I read is not what I'm expecting:

cat /dev/ttyAMA0
BPT@3L623@1|
G]JF8Ic 
@*.5 |
8j@6M&S
8
0LS c
.@*|
@rjE@1Va
@` @c
@0Ka
^C

Any pointers or help would be greatly appreciated.