* [[AMSSIO]] (RS232 interface) (DIY)
* [[Amstrad Serial Interface]]
* [[Cirkit serial interface]]
* Commstart v21/23 modem
* [[CPCI RS232 Interface]] (DIY)
* Digitelec DTL 2000/2100 Modem
* [[KDS Electronics]] [[KDS_CPC_serial_interfaceKDS serial interface|CPC Serial Interface]]
* [[Virtual Net 96]] ([[Wizcat]])