SC518 is a Z80 CPU card designed for Z50Bus.

This card provides a Z80 CPU with a choice of clock sources.
The main features are:
- Z80 Central Processor Unit (CPU)
- Jumper to select one of 5 clock sources:
- Half-size (8-pin DIP) “can” oscillator (x 3)
- Bus pin USR1
- External pin
- Typical clock speed 7.3728 MHz
- Compatible with memory card SC519
This card is designed to allow easy selection of a number of different clock sources for the Z80 CPU.
A typical system will also require:
- Backplane (eg. SC501)
- Power supply (eg. SC502)
- Memory card (eg. SC519)
- Serial card (eg. SC521)