The module says VFD2041 REV1.4 on it. I don't see any PCB revision number. How do I modify it to establish I2C?

I tried addressing the VFD2041 with 0x5C, but I still did not receive an acknowledge from the module.

Any other suggestions?

I am trying to interface a VFD2041 Rev 1.4 display to an Atmega16 microcontroller. I followed the instructions in the Atmega16 datasheet for I2C communication, and attempted to transmit data to the display. The display does not acknowledge its I2C address. Jumpers J1 and J2 are set, so according to ...