DCT4 platform

The Nokia DCT4 platform or Digital Core Technology 4 is a hardware platform used on Nokia phones from the early to mid 2000s. Some basic phones from the late 2000s also used DCT4, but this is often called DCT4+. It was succeeded by the BB5 platform.

DCT4 is based on two ASICs: UEMEK (Universal Energy Management) and UPP (Universal Phone Processor).

UEM
The Universal Energy Management ASIC controls giving power to other components, including the UPP.

UPP
The Universal Phone Processor contains the MCU, DSP and RAM. In later DCT4 devices, sometimes called the DCT4.5 generation, this was replaced by the TIKU.

The UPP model of a phone can be checked from its Level 3-4 service manual, in the "System Module", "sysmod" or "system" section. If you can find the exact CPU frequencies, please add them to this list.

Firmware
Firmware for DCT4 devices can be found on archive.org. DCT4 generation firmwares are encrypted, but they can be extracted or modified with tools such as TriX.