Software was supplied on ROM, mostly comprising utility commands for hobbyists rather than a comms application per se - though there was limited terminal emulation for connecting to the then-popular [[Prestel]] service]. The original, UK version included commands for file transfer entitled |SUCK and |BLOW, which used a proprietary Amstrad format similar to [[XModem]]-1k but, annoyingly, subtly incompatible. These commands were reputedly renamed for the US edition to avoid causing offence.
The French company [[Mercitel]] sold a custom version of this interface, replacing the original 8k ROM with an 16k Rom adding a [http://en.wikipedia.org/wiki/Minitel minitel] emulator.
Because of the external power supply and the poor quality of the software, this model failed to establish itself as the "standard" serial interface in the way that (say) the [[DDI-1]] did for disc drives. This allowed other serial interfaces to flourish, such as those sold by [[Cirkit]] and [[KDS]].
=== Pace serial interface (1986) ===
As a result, Amstrad dropped their original design and instead chose to remanufacture a [[PACE]] design. This included significantly improved hardware (a more compact interface thanks to SMD components and no external PSU) and vastly superior software. However, this redesign also scarified the quality of RS232 signalling voltage by using 0V/5V output voltage instead of -12V/12V.
The software was a ROM version of the [[Commstar]] terminal utility from [[HoneySoft]]. This was a user-friendly program with standard [[XModem]] file transfer functions. However, one foolish design decision was the idea of using a 24x80 screen with a single-line status display - though presenting a good user interface, this forced the use of software rather than hardware scrolling, making the interface unusable for terminal emulation at any speed above 2400 baud.
Image:Amstrad rs232 2.jpg|The original Amstrad serial interface
Image:Amstrad rs232 power1.jpg|The original powersupply that came with the interface
Image:AmstradRS232PSU_Rating.jpg|The original powersupply rating
Image:Amstrad RS232C Box.jpg|Old interface, boxed
Image:Amstrad RS232C Device.jpg|Old interface with PSU
* [[Media:RS232101.ZIP|ROM Image for original version]] - 8K ROM
* [[Media:RS232Mercitel14.rom|ROM Image for Mercitel version]] - 16K ROM
* [[Media:AmstradPaceSerialInterfaceCommstarRomImage.zip|ROM Image for Pace version]] - Commstar 32K ROM (two 16K banks)
* [[Media:PACE232.ZIP|ROM Image for Pace version]] - Commstar 32K ROM
[[Category:Peripherals]] [[Category:Serial_interfaces]][[Category:Amstrad Products]][[Category:Expansion ROM]]