Matrix Orbital LK202-25 Legacy - Manual (Page 15)

2.2.2 TTL Communications
A standard DB-9F or 4 pin power connector/communication (female) connector is needed for TTL com-
munications. Power may also be supplied via this connector if desired. A PC is not to be used when TTL
communication is established via a direct com port. One modification is required for TTL. The jumps must
be removed from the RS232 selection and placed on the TTL selection.
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
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