Make this my favourite Interface 1bis for the Sinclair ZX Spectrum (Delivery 30-60 days)

Retro Computers >> Sinclair >> Sinclair ZX Spectrum >> Hardware >> General / Add-Ons
Listing type:
Fixed Price Multiple Items
Item Condition:
Seller location:
Randpark Ridge, South Africa
Ending in:
This listing is closed (31/12/2018)

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Latest buyer:
a***n (8)
Fixed price:
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From only £11.00 or buyer collect
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Number Sold:
53 (View history)
Buyer Value Date and hour Quantity bought
a***n (8) £26.15 16/10/2018 21:53:47 1
m***s (6) £26.15 15/10/2018 13:55:33 1
l***4 (0) £26.15 02/10/2018 14:30:44 1
G***k (12) £26.15 01/10/2018 04:12:46 1
a***a (60) £26.15 22/09/2018 10:43:20 1
M***4 (1) £26.15 21/08/2018 21:02:43 1
m***o (2) £26.15 16/08/2018 23:15:18 1
N***o (2) £26.15 21/07/2018 17:24:15 1
P***I (0) £26.15 19/05/2018 18:09:13 1
s***4 (2) £26.15 19/05/2018 11:48:29 1
c***o (1) £26.15 16/02/2018 12:04:11 1
F***t (2) £26.15 03/02/2018 05:40:59 1
p***n (3) £26.15 29/01/2018 19:56:33 1
h***y (38) £26.15 27/01/2018 15:03:10 1
N***x (1) £26.15 26/01/2018 17:25:55 1
t***e (0) £52.30 07/01/2018 00:03:24 2
I***s (9) £26.15 04/01/2018 20:00:24 1
m***i (6) £26.15 29/12/2017 12:47:07 1
w***r (7) £26.15 11/12/2017 09:04:43 1
w***h (0) £26.15 10/12/2017 21:45:25 1
K***s (0) £26.15 08/12/2017 00:08:34 1
T***r (2) £26.15 25/11/2017 15:07:24 1
S***y (4) £26.15 23/11/2017 09:02:23 1
v***y (6) £26.15 22/11/2017 11:55:59 1
p***0 (5) £26.15 29/10/2017 06:04:54 1
l***e (4) £26.15 25/10/2017 21:24:38 1
c***t (31) £52.30 25/10/2017 17:03:55 2
v***5 (2) £26.15 22/10/2017 23:34:51 1
h***e (9) £26.55 19/10/2017 09:11:07 1
T***s (8) £26.55 27/09/2017 12:40:19 1
C***r (0) £53.10 30/08/2017 22:58:47 2
J***o (1) £28.00 19/05/2017 16:29:46 1
h***r (9) £28.00 18/05/2017 12:28:51 1
d***a (2) £28.00 23/03/2017 03:01:49 1
p***3 (10) £28.00 14/03/2017 22:18:45 1
a***o (15) £28.00 05/02/2017 10:17:05 1
r***h (9) £28.00 21/01/2017 18:53:04 1
d***s (1) £28.00 31/12/2016 11:55:40 1
z***p (15) £28.00 29/12/2016 20:21:18 1
f***x (4) £28.00 24/12/2016 16:22:34 1
t***4 (4) £28.00 11/11/2016 09:43:24 1
p***e (4) £28.00 18/10/2016 20:43:22 1
a***r (2) £28.00 02/10/2016 19:25:47 1
G***f (2) £28.00 02/10/2016 03:24:36 1
B***e (1) £28.00 25/09/2016 23:51:16 1
h***r (3) £28.00 19/09/2016 23:33:09 1
x***n (3) £28.00 30/08/2016 21:35:15 1
r***t (23) £28.00 30/08/2016 20:10:59 1
a***g (19) £28.00 26/07/2016 19:59:05 1
T***s (20) £28.00 24/07/2016 23:54:04 1
Feedback on this Item
PositivePositive a***n (8) 29/01/2019 21:56:30
PositivePositive m***s (6) Excelent fast 20/11/2018 13:48:03
PositivePositive a***a (60) packed very well, arrived safe and sound, thank you for a great product. 18/10/2018 19:59:25
NegativeNegative m***o (2) AVOID! Received faulty item which fried my Spec. Dan treats buyers like dirt as others have already said. Blocked on FB after requesting refund. AVOID 13/11/2018 23:07:13
PositivePositive s***4 (2) Arrived safely. Thanks Dan 04/07/2018 11:26:36
PositivePositive F***t (2) Works very well with my TS-2068 + twister board. Lots of powerful features. Thank you! 29/08/2018 03:01:29
PositivePositive N***x (1) Jestem bardzo zadowolony :) POLECAM !!!! :) 07/04/2018 21:02:25
PositivePositive v***y (6) 02/09/2018 08:43:16
PositivePositive l***e (4) Thank you Dan, package arrived, all is perfect conditions. Pleasure doing business with 18/11/2017 12:08:05
PositivePositive v***5 (2) Arrived quickly, safely packaged.The most complete interface for the ZX (LFN,mouse,usb to pc), and it can play loading sound into EAR! Thank You Dan ! 17/11/2017 06:28:32
PositivePositive h***e (9) Superb product, can't recommend enough. Thanks! 14/11/2017 13:01:36
PositivePositive T***s (8) No problems at all - thanks! 23/11/2017 14:22:24
PositivePositive C***r (0) Great item! Great and communicable author! Helped me with my problem with my grey +2! Very very good seller! 07/10/2017 03:04:15
NegativeNegative d***a (2) Sold broken interface, cannot deal with him, blaming me. Avoid as you wont be able to sort out anything with this seller. NOT RECOMMENDED !!!!!!! 15/04/2017 15:07:48
PositivePositive d***s (1) Well built and thought out PCB, pure brilliant, Thanks Dan!! 20/01/2017 22:09:06
PositivePositive f***x (4) A really powerful tool. 17/01/2017 09:06:26
PositivePositive t***4 (4) Fantastic seller Amazing comms and swift delivery highly recommended. 22/11/2016 11:59:36
PositivePositive B***e (1) Excellent seller. 5 star product! Now I can revive good old times ;) 01/11/2016 22:45:23
PositivePositive a***g (19) Most satisfied. Thank you! 09/08/2016 17:43:18
PositivePositive T***s (20) Great Product and the best customer support. 17/08/2016 02:40:36

Item Number : 18033

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    The ‘Interface 1bis’ is the only ZX Spectrum expansion device that features the combined functionality of

- Local storage, of up to 8 GB, subdivided in logical drives of 32 MB, on one micro SD card.

- Remote storage, of unlimited size, with long filename support, on a server machine, connected via a full-speed USB port.

- Non-volatile 128 KB RAM drive, for application that need to store data frequently and fast.

- Kempston joystick port.

- PS/2 mouse port, producing Kempston mouse or Kempston joystick output. 

  Following devices are also supported by the operating system and are automatically identified, when attached to the mouse connector:

    PS/2 keyboard

    Asynchronous serial communication cable, with or without a RS232 trans-receiver

    Serial printer, through a RS232 trans-receiver

    Parallel printer, through a serial to parallel adaptor 

    'EAR' cable for rendering tape files as audio signal

- Ethernet connectivity, by means of an optional, third party, add-on module.

- Maximum software compatibility to the original 'ZX Interface 1' of Sinclair Research Ltd.

- Enhanced 'Extended BASIC' with comprehensive random-access file handling capabilities and full emulator (.TAP and .Z80) files support. Files in .TZX format can be loaded either directly, if they contain only normal speed blocks, or otherwise, using the built-in 'tape player' and the 'EAR' cable.

- Integrated Game Browser and File Manager, with mouse and joystick control, being able to access besides the on-board SD card and a server PC, connected to the USB port, up to seven networked 'stations', which can be PCs or 'Interface 1bis' units, over the Internet, as well as the games und utilities archive of the 'Word of Spectrum' site.



    The navigation functions include jumping to a given display page as well as advanced search facilities.

    When a game is downloaded from the 'Word of Spectrum' archive, the associated screenshot, info and POKE files are also retrieved and transparently linked to the relevant game. POKEs management includes the selective enabling of 'trainers', which are then automatically applied when the corresponding game is launched.

    Both 48k and 128k snapshots can be created without interrupting the game, just by pushing the interface's button. The application manages snapshots transparently to the user, maintaining always two different copies in order to allow both restarting the game from the last 'good' situation, in case of unsatisfactory progress, or securing the attained progress.

    The application can perform the full range of file management functions, including complex ones, like moving entire directory trees, between any 'locations', for example between an 'Interface 1bis' unit in New Zeeland and a PC server in Argentina.





    The key to its versatility is the distinctivearchitecture of the IF1bis, which offloads all peripheral I/O operations onto a microcontroller, connected directly to the system’s data bus. This simplifies the design to a great extent and in conjunction with a rationalized memory configuration, requiring just one 32KB non-volatile SRAM chip, adds considerable benefits like:

- Small PCB size, of under 0.5dm2, allowing a

- Zero desk foot-print, due to vertical mounting.

- Simple, two-layer, PCB layout with very short tracks, for reduced noise.

- Low power consumption: at under 75mA, the lowest among comparable devices

- Low bus load: unequalled at only 0.7µA data bus leakage and only 0.5µA plus 1 (one) standard CMOS load on the other lines.

- Improved peripheral device handling, as the microcontroller, with its multiple hardware timers and complex interrupt logic, is specialized and better equipped for this task than the ZX Spectrum’s CPU.

- Faster transfer between local and remote storage as it is performed directly by the microcontroller, via its USB and SPI ports, bypassing the ZX Spectrum.

- Simplified operating system, needing only one device driver: for the ‘Parallel Slave Port’ of the microcontroller, which in turn handles all low level peripheral control operations.


The IF1bis has certain special features, not encountered on comparable devices, as no compromise on robustness was made in the process of optimizing the performance / cost ratio:

- The non-volatile SRAM is protected by an adjustable, high precision, voltage supervisor IC.

- The control push-button is de-bounced and multiplexed using a dedicated microcontroller, which generates clean, digitally timed, RESET and NMI signals.

- The /ROMCS line is driven not through transistors, but a Low-Voltage CMOS buffer, to ensure fail-safe memory paging.

And last, but not least:

- Unlike most ZX Spectrum add-ons, the IF1bis does not perform hardware trapping and can therefore function even if the host machine's CPU has a faulty /M1 line.

- The IF1bis does not rely upon the host machine's CLK line, which on some ZX Spectrum models is unusable.



    Operating system


The ‘Interface 1bis’, as the name intends to suggest, is 100% software (backward-) compatible to the ‘ZX Interface 1’ of Sinclair Research, in respect of ‘Microdrive’ storage operations, as well as RS232 and ZX Network communication, both at BASIC command and ‘hook code’ level, yet not in 128k BASIC mode. 


All file handling operations can equally be performed on any of the two implemented file systems:

- block device, for a SD card (device "M") or the RAM drive (device "R")

- file device, for a PC server (device "V"),

either local or remote, over an IP network.


The main enhancements to the ‘extended BASIC’ of the original ‘ZX Interface 1’ are:

- The file size limit is 16 MB.

- Sequential access is not restricted to ‘PRINT’ files.

- Sequential access ‘M-channels’ can be selectively opened for input or output.

- Data in memory can be read, written or verified, through direct random access, to (or from) a specified position in a file, of any type, without the need to OPEN it.

- Random access ‘file handles’ can be used to more conveniently reference files and automatically keep track of their random access pointers.

- Both sequential access pointers of ‘M-channels’ and random access pointers of ‘file handles’ can be moved to any position.

- Abbreviated syntax, allowing the omission of the ‘device type’ and ‘drive number’ fields in a statement, if they are the same as in the previous one.


The operating system of the ‘Interface 1bis’ has a very long development history, being written in 1994 and since then constantly improved and adapted to new hardware configurations. It is a mature, stable product, tailored to practical needs and offering arguably unrivalled functionality, speed and ease of use.



    Technical conditions of use


The ‘Interface 1bis’ should not be attached or removed while the ZX Spectrum is powered.


 - An edge receptacle with softer contacts was deliberately chosen for the ‘Interface 1bis’, in order to reduce wear and tear. Therefore, the ZX Spectrum’s board edge must be in a fairly good condition, without grooves or asperities. Otherwise, due to bad electrical contact, the ZX Spectrum may hang or behave erratically and the interface’s operating system may become corrupted, after switching to the ‘Active’ mode. In such a situation it is necessary to smoothen the ZX Spectrum’s board edge with a hard rubber eraser and apply an adequate lubricant, like Electrolube EML, after which the operating system has to be restored, as shown in the ‘Troubleshooting’ video tutorial.


- The ‘Interface 1bis’ cannot be switched to ‘Active’ mode if the supply voltage is too low, as its voltage supervisor disables memory paging whenever it drops below 4.75V for longer than 2 micro-seconds. This problem occurs mainly with 128k +2 (grey) models and can be solved only by replacing the 5V regulator of the ZX Spectrum.








Picture gallery

  • Interface 1bis for the Sinclair ZX Spectrum (Delivery 30-60 days)
  • Interface 1bis for the Sinclair ZX Spectrum (Delivery 30-60 days)
  • Interface 1bis for the Sinclair ZX Spectrum (Delivery 30-60 days)

Youtube Video

Questions and Answers

  • Question: Can I use it with 128 tost rack? Can I save basic code on SD card?

    Posted by m***s (6) - 03/07/2018 13:32:37

    Answer: 1. Yes the 'Interface 1bis' works with all Sinclair/Amstrad ZX Spectrum machines, yet not in 128k BASIC mode. 2. Yes, for details please read the 'Getting started guide'

  • Question: What is the exact name or search term for this Ethernet add-on module?

    Posted by R***k (33) - 14/05/2018 06:25:38


  • Question: hola esta es la version que tiene wifi? gracias

    Posted by e***7 (0) - 20/10/2017 16:23:44

    Answer: For technical reasons the WiFi plug-in cannot be sold here. You can cancel this order and purchase the 'Interface 1 bis' unit + a WiFi plug-in at the official web site

  • Question: Received your well built board yesterday (13/1/17) Thanks Dan! I have a 128k 'toastrack' , but can't get the Menu to load, does it have to be a 4-8gb HCSD card, as only got a 2gb Sandisk at moment, Thanks, Col.

    Posted by d***s (1) - 14/01/2017 21:46:11

    Answer: Obsolete SD cards, of less than 4GB, are not supported anymore, as they have not been commercially available for many years.

  • Question: Do you have any of the Ethernet add-on modules fro sale? If not, where can I purchase one? Thanks.

    Posted by z***t (18) - 22/09/2016 08:57:50

    Answer: The ethernet module can be purchased on eBay for less than USD 3.00, including shipping, but you'll also need an 'SPI cable' which is available as an optional accessory at the 'Interface 1bis' website or on eBay

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Shipping and Payment

Item Location:
Randpark Ridge, South Africa
Shipping conditions:
Buyer pays shipping expenses
Shipment fee:
  • To South Africa :
  • Collection in Person : FREE
  • To EU :
  • Intl Signed For : £11.00 For initial item, £11.00 Per additional item
  • To Rest of Europe :
  • Intl Signed For : £11.00 For initial item, £11.00 Per additional item
  • To Americas :
  • Intl Signed For : £11.00 For initial item, £11.00 Per additional item
  • To Rest of World :
  • Intl Signed For : £11.00 For initial item, £11.00 Per additional item
Shipment terms:
Shipped by registered air mail.
Can be tracked.
Normal delivery time: under 30 days.
During festive season or strike actions: up to 60 days
Payment methods:

The seller accepts all responsibility for this listing

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