Matrix Orbital GLK24064-25 Legacy - Manual (Page 14)

This will allow TTL RS-232 levels of communication through the DB-9 connector or the power connec-
tor.
2.2.3 RS-232 Communication through the Power Connector
RS-232 communication can also be achieved through the middle two pins of the power connector.
Figure 12: Power Connector
Table 4: Connector Pinout
Pin 4 Ground
Pin 3 Rx
Pin 2 Tx
Pin 1 Vdc
To allow this, the jumpers must be set as indicated below;
Figure 13: RS-232
2.2.4 I 2 C Communications
The display has I 2 C communications running at 100 Kbps and up to 127 units can be on a single com-
munications line. The display’s I 2 C communication lines are the two middle pins of the power connector.
They are shared with RS-232 and have to be turned on. The I 2 C data line operates on 5 volt CMOS levels.
The default I 2 C address is 0x50.
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