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yann64andClaude Opus 5.5 b274874139 All machines linked to their forum thread (full comment import)
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2026-10-13 17:26:43 +02:00

8.9 KiB

title, categories, types, origins, years, cpus, params
title categories types origins years cpus params
Merlin Tonto
Computers
Professional Computer
United Kingdom
1985
68008
name image company company_name specs tabs forum_thread photos hardware oc_id source
Tonto /media/museum/photos/merlin_tonto_rightside_1.jpg /companies/merlin Merlin
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NAME Tonto
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MANUFACTURER Merlin
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TYPE Professional Computer
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ORIGIN United Kingdom
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YEAR 1985
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END OF PRODUCTION maintained up to 1993
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BUILT IN LANGUAGE None
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KEYBOARD Full stroke 73-key with numeric keypad
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CPU 68008
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SPEED 7.5 MHz
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CO-PROCESSOR Sinclair ULA custom chip
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RAM 128 KB, up to 256 KB + 2 KB of battery-backed RAM
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VRAM 32 KB (from the main RAM)
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ROM 128 KB, up to 320 KB using ROM packs
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TEXT MODES 42 or 64 or 84 chars. x 24 lines
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GRAPHIC MODES 256 x 256 (8 colors) / 512 x 256 (4 colors)
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COLORS 256
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SOUND TI TMP5220C speech synthesiser / built-in loudspeaker
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SIZE / WEIGHT 44 (W) x 26.5 (D) x 6.8 (H)
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I/O PORTS Custom connectors for ROM pack and Telephony module, Serial printer, RGB Monitor
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BUILT IN MEDIA 2 x 100 KB microdrives
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OS Tonto OS
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POWER SUPPLY Power is supplied by the monitor
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PRICE £1,500 at start. Sold to British Telecom staff for £100 complete when BT stopped to maintain them.
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hardware
852
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SYSTEM /media/museum/photos/merlin_tonto_system_1.jpg
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LEFT SIDE /media/museum/photos/merlin_tonto_leftside_1.jpg
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KEYBOARD CLOSE-UP A demo program cartridge and BASIC cartridge are inserted in both microdrives /media/museum/photos/merlin_tonto_keybcloseup_1.jpg
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COLOUR MONITOR Pronto with Merlin 14" colour monitor. /media/museum/photos/merlin_tonto_colourmon_1.jpg
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MONOCHROME MONITOR /media/museum/photos/merlin_tonto_monochrommon_1.jpg
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RUNNING Pronto and monochrome monitor running Xchange Task Control. /media/museum/photos/merlin_tonto_running_1.jpg
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BACK SIDE **(1)** ROM-pack\ **(2)** Serial printer DB9 connector\ **(3)** RGB video out and power input DB15 connector. Power is supplied by the monitor\ **(4)** Telephony module with two telephone lines /media/museum/photos/merlin_tonto_back_1.jpg
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ROM-PACK The ROM-pack module itself contains Xchange, a 4 elements business applications package originally made by PSION for the Sinclair QL and including QUILL, ABACUS, ARCHIVE and EASEL.\ Several optional ROM cartridges could be added. Here, Datalink 2, Interfile and Messaging applications are inserted. /media/museum/photos/merlin_tonto_rompack_1.jpg
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INSIDE For more information about Tonto mainboard, see [OPD motherboard](/museum/icl-opd-one-per-desk/) picture. /media/museum/photos/merlin_tonto_inside_1.jpg
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CPU BOARD A piggy-back board carries the 68008 CPU **(1)**, 4 ROM chips **(2)** holding the Tonto operating system, and the Texas Instruments TMP5220C speech synthesiser IC **(3)**, which has 16 KB of custom ROM. /media/museum/photos/merlin_tonto_cpuboard_1.jpg
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DUST COVER /media/museum/photos/merlin_tonto_dustcover_1.jpg
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TAPE CARTRIDGES Various software on microdrive tape cartridges.\ Right ones are empty. /media/museum/photos/merlin_tonto_tapecart_1.jpg
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CARTRIDGES CASES Original Merlin tape cartridges cases /media/museum/photos/merlin_tonto_tapecart_2.jpg
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DATA COMMS ADAPTOR The Data Comms adaptor enabled the TONTO to be used as a computer terminal.\ Profiles of various terminals could be entered and stored in the adapter. Each profile could be set to match the specification of the terminal to be emulated.\ The TONTO could emulate VT100, VT52 and Teletype terminals, or could be configured to operate with protocol convertors.\ A serial connector insured the link to a host computer. /media/museum/hardware/merlin_tonto_datacom_1.jpg
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ROM-PACK/6 A rare ROM-pack version allowing six ROM cartridges to be inserted and used simultaneously.\ Only 20 ROM-packs of this type were built. /media/museum/hardware/merlin_tonto_rompack6_1.jpg
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TELELOCK This add-on was firmly fixed to the TONTO case so that only the key owner could use the computer. /media/museum/hardware/merlin_tonto_telelock_1.jpg
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url date
https://web.archive.org/web/20230608083856/http://www.old-computers.com/museum/computer.asp?c=871 2023-06-08

The Tonto was the same model as the ICL OPD and the Telcom ComputerPhone which was intended for Australian market. Like the ICL version, the Tonto was sold only in the U.K. It was born thanks to a collaborative venture between British Telecom, ICL and Sinclair Research. The designers idea was to build a centralized desktop information system able to access online services, mainframes and other similar systems through the British Telecom network.

It was essentially a Sinclair QL at heart, featuring the same 68008 processor. Applications software were stored in plug-in ROM cartridges or Microdrive tapes. Sadly, both of them were not compatible with QL interfaces and microdrives format and the specific Tonto O.S. couldn't run ordinary software made for the QL, even in BASIC language.

However, the most interesting aspect of the Tonto was its telephony integration. Its internal modem (300 an 1200/75 baud) could manage two telephone lines, and the Tonto, could be used as an intelligent answering machine thanks to its synthesised voice response (but no record capabilities), a Prestel terminal for Videotext services as well as a specialized peripheral and multi-protocols terminal for mainframes. Several interconnected Tonto's also could automatically exchange files and information between them.

Below are prices for the Tonto at is launch, taken from a BT promotional video for the Tonto, dated 29-4-1985.

£1245 Basic Mono Machine
£1375 Basic Mono Machine with Xchange
£1675 Colour Machine
£1805 Colour Machine with Xchange
These are all Excluding VAT.

So these are the final prices.
£1462 Basic Mono Machine
£1615 Basic Mono Machine with Xchange
£1968 Colour Machine
£2120 Colour Machine with Xchange

Then you had an optional printer and many optional ROM packs. This was quite an expensive piece of desk accessory in its day.


Contributors: Pete (UK)

Additional information from Ray Axford:
Apart from the black and white screen that came with the standard one, you could also get larger 14" colour monitor. You could also attach by ribbon cable an additional plug-in double external 3.5" floppy drive. I used to maintain these for British Telecom and have the technical manual.
I used it for many years, extracting info from Prestel network. Lovely machine - nothing to match even today, with the built in handset on the keyboard. You could also use it hands free, with loudspeaker.

About the "T" logo, Stan Lee specifies:
I recently noticed the rather bizarre T on the Merlin Logo. I knew I recognized it somewhere-- Then it hit me. That T is the 2nd half of an old BT logo... that's probably why there's a phone attached, I suppose.

Tim Jenner adds:
The Tonto was pretty unreliable - powered up all the time, the PSU's eventually died. The microdrives were less than perfect too.
You could get expanded rom packs including more memory, but most common was the Exchange rompack which included the Psion Exchange office suite. Quill was excellent!

Bill Perry reports:
These were sold through BT local area sales as well as into bigger projects through BT Field Services. The bigger projects included Customs & Excise at ports and the Home Office Prison Services (HOPS) project. The tape drives were unreliable!

We need more info about this computer ! If you designed, used, or have more info about this system, please send us pictures or anything you might find useful.