| Connector pin-out | Arduino test rig |
| Pin# | IC pin | Label | Pin | colour |
| 1 | VSS | Ground terminal of module | | |
| 2 | VDD | Supply terminal of module | | |
| 3 | VO | Power supply for Liquid Crystal Drive | | |
| 4 | RS | Register select signal | | |
| 5 | R/W | Read/Write selection: High = Read, Low = Write | | |
| 6 | E | Enable signal | | |
| 7 | D0 | Bi-directional Data Bus | | |
| 8 | D1 | Bi-directional Data Bus | | |
| 9 | D2 | Bi-directional Data Bus | | |
| 10 | D3 | Bi-directional Data Bus | | |
| 11 | D4 | Bi-directional Data Bus | | |
| 12 | D5 | Bi-directional Data Bus | | |
| 13 | D6 | Bi-directional Data Bus | | |
| 14 | D7 | Bi-directional Data Bus | | |
| 15 | CS1 | Select IC U2 (active high) | | |
| 16 | CS2 | Select IC U3 (active high) | | |
| 17 | RSTB | Reset signal (active low) | | |
| 18 | VOUT | * Negative voltage from the LCD Module | | |
| 19 | SLA | Backlight power supply | | |
| 20 | SLK | Backlight ground | | |