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 and no external PSU) and vastly superior software.
The software was a ROM version of Pace's the [[Commstar]] terminal utility, from [[CommstarHoneySoft]]. 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.
== I/O Ports ==