Matrix Orbital PK202-25 - Manual (Page 15)

Figure 12: TTL Select
Note that this device uses signal levels from 0V to + 5V on the TTL setting.
Table 6: RS-232 Pinout
Pin Number Direction Description LCD Host
2 Data from LCD Data out (LCD) Tx Rx
3 Data to LCD Data in (LCD) Rx Tx
5 - Ground gnd gnd
For TTL communication via the 4 pin connector, please see the figure and table below:
1 2 3 4 1 2 3 4
Figure 13: Power Connector
Matrix Orbital PK202-25 11