Documentation
Details about the original SPECTRA interface can be found in its user manual, which is styled to match the original Spectrum BASIC programming manual.
A supplement manual is available detailing the functionality specific to the SPECTRA+128 interface and its differences to the SPECTRA interface.
The manual also contains details of the SPECTRA+3 Adapter board, and wiring differences between a RS232 data cable and a RS232 printer cable
(with is also applicable to the SPECTRA interface). The manual is only available as an electronic download.
The cover illustration used for both manuals is by John Harris and is used with kind permission. Prints of his artwork used for the original ZX Spectrum manual covers
are available from:
www.alisoneldred.com/thumbsJohnHarris-Prints-3-1.html.