The SC511, serial and timer card houses a Z80 SIO chip, which provides two TTL serial ports for use with FTDI style serial adapter cables, and a Z80 CTC, which has four counter/timer channels.

The main features of this card are:

• Z50Bus compatible (“Standard” card size 100mm x 75mm)
• Full Z80 mode 2 interrupt support (IEI/IEO daisy-chain)
• Interrupt look-ahead circuit
• Two TTL serial ports for use with FTDI serial adapter cables
• Software control of baud rate for both ports
• On-board oscillator for independence from CPU clock rate
• Clock tick timer
• Two I/O address options
• Optional connection of either port to Z50Bus RX/TX pins