To clarify:
Dip switch one controls the data input settings. There are also small jumpers nearby that tell the display whether or not it is "first" in line or a display later on in the string.
Dip switch one has 8 positions.
9600,n,8,1
1 off (off is down)
2 on (on is up)
3 off
4 off
5 off (turning 5 on starts self test)
6 off
7 off (self test A-Z) (on self test all dots rotate)
8 off
Dip Switch 2 controls the personality of the line. This Switch is read only on power on so you have to reboot sign if a change is made.
All switches are off (down) except:
Line one = 1 on (on up)
Line two = 2 on
Line three = 1 & 2 on
Line four = 3 on
Line five = 1 & 3 on
Line six = 2 & 3 on
Input to the displays
PC pin 5 ground = Display pin 1 & 4 jumped ground
Pc pin 3 transmit = Display pin 5 receive