Which LCD to use with this sketch

I am building a diy motion control system for timelapses. Writing an advanced sketch to control the 3-axis system is too hard for me, so I am planning to use the open-source code of the Emotimo TB3 Black. It uses an Arduino Mega 2560, but I have no idea what kind of LCD they are using.

-I tried using a I2C Serial LCD with a sdl, sda, 5v and gnd, but it didn’t work.
-The code uses a library called NHDLCD9.
-The library says it is based on the Newhaven Design LCD with Softwareserial compatibility.
-The code “prints” to the lcd using: Serial.print(“text”).
-The LCD is connected with three wires: 5v, GND and a wire to digital pin 4.
-The sketch is able to adjust the contrast and backlight brightness.
-The LCD is 16x2
-The sketch sends some sort of commands to the lcd, by serial printing 0xFE and for example 0x48.

While the library says it uses the Newhaven LCD, this LCD has many more pins than just 3.

I searched the web and I came to these options:
-Use an LCD with a 5v, gnd, TX and RX pin. Then just connect only yhe TX or RX pin to digital pin 4.
-Use a Newhaven LCD and use an unknown module to connect it to 3 pins.
-Use a normal LCD + this Serial Backpack: https://www.sparkfun.com/products/258

It would be awesome if somebody knows which LCD I could use.

TB3_Black_109_Release1.ino (56.4 KB)

NHDLCD9.cpp (3.85 KB)

NHDLCD9.h (3.06 KB)

Looking at the Newhaven SERIAL LCD modules on their website they clearly show three sets of connections, a 3 pin RS232 connection of RX, Vss & Vdd, a 6 pin connection for I2C or SPI, and a 4 pin connection for backlight.

Ah yes, stupid of me. I suppose I overlooked it after searching the web for hours :confused: