en:companias:sca_systems []

TECHNICAL DATA

NAME:SCA Systems Ltd.

ORIGIN:Ferring, West Sussex, England (UK)

FOUNDED:c. 1986

STATUS:Historical (Inactive / Dissolved)

SPECIALITY:Memory Expansions, Communication Interfaces, and Hardware Clocks

OFFICIAL WEB:Does not exist

Description

SCA Systems Ltd. was one of the most respected and important electronic engineering and expansion peripheral firms within the professional Amstrad PCW ecosystem during the 1980s and 1990s. According to hardware reviews published in British press titles such as 8000 Plus, SCA Systems successfully targeted the high-end corporate and industrial market. Its catalogue provided critical hardware expansions that solved the strict connectivity and memory shortages native to the Joyce range, enabling thousands of British and international offices to link their terminals to external data networks, advanced telecommunication modems, and massively expand the RAM to run complex spreadsheets and large databases.

Developed Hardware & Interfaces

RamPac 512k High-end external RAM expansion module, originally retailed at a launch price of £149.95. Designed to attach cleanly to the rear edge expansion bus of the PCW 8256/8512 models, this hardware utilized ingenious integrated circuitry logic to manage an additional 512 KB bank via electronic bank-switching mapped through hardware-specific Input/Output ports. By creating a switching 'window' within the native 64 KB addressable space of the Z80 processor, it allowed the configuration of high-speed, massive virtual disks (RAM Disks) under CP/M in a way completely transparent to the operating system, bypassing the physical mechanical slowdowns of 3" floppy disks. Serial Parallel Interfaces Professional Industrial-grade adapter module analyzed in publications such as Amstrad Computer User and sold for £59.95. Based on the standard INS8250 UART controller chip (the same integrated chip used in the IBM PC compatible architecture), it provided one 25-pin RS-232 serial port (DB-25) and one Centronics parallel port. Its board design featured optocouplers and an electronic signal isolation system to shield the PCW mainboard signal lines, allowing users to redirect print outputs from LocoScript and flat files toward standard commercial Epson dot-matrix or early professional laser printers. Serial Parallel Interfaces Professional Plus The most advanced communications circuitry revision from SCA, launched at a price of £79.95 across the advertising pages of 8000 Plus. Specifically engineered to solve the chronic data character loss and synchronization errors (Buffer Overrun) when users attached advanced telephone modems at transfer rates exceeding 2400 baud. The firm redesigned the expansion card by implementing the legendary high-speed NS16550AN UART, which incorporated a 16-byte internal FIFO buffer memory that absorbed massive background data transmissions without saturating the Z80 microprocessor processing cycles, enabling fluid baud rates up to 9600 for terminal emulation connected to mainframes. SCA Real Time Clock (Real-Time Clock) Complementary chronological hardware expansion featuring a built-in long-life lithium battery. Designed to address the lack of a backed-up internal system clock in the Amstrad PCW range (which forced operators to manually type the date and time on every boot sequence), this hardware immediately injected accurate temporal data into the CP/M internal registers during startup bootstrap, ensuring that file timestamping for office documents and RAM disk files was completely automated and accurate.

Support Software & Integration

SCA Comms Software / Terminal Utilities Native telecommunication software suites distributed on floppy disks under the CP/M environment, coded to squeeze the maximum throughput from the FIFO buffers of the Professional Plus interfaces. They supported advanced VT100 terminal emulation alongside sector-based file transfer protocols such as XMODEM, YMODEM, and Kermit, allowing the PCW to connect remotely to Bulletin Board Services (BBS) and early pre-Internet network gateways in the late 1980s. SCA RAM & Clock Driver Block An executable system extension block with a .FIB file format that users copied directly into the boot sector of their master LocoScript or CP/M disks. During machine initialization, this background code intercepted the native PCW BIOS to register the expanded bank of the RamPac 512k in the logical memory vectors and automatically synchronize the timer of the physical SCA hardware clock integrated chip.

Known Addresses (England, UK)

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Engineering Headquarters and Distribution Offices 61 Ferringham Lane, Ferring, West Sussex (Postcode: BN12 5LW, England) Original technical support and mail order telephone contact: Phone 0903 700288