Byte-Back Co

BYTE-BACK started producing peripherals for the Sinclair computer in 1981.

Their first product, a relay controller, was used by customers to control and automate projects.

The original owner closed the company in the mid-1980s. David Leech, a former employee, purchased the company and continued to sell existing inventory.

In the late 1980s, Leech introduced multifunction controllers for the IBM PC.


With the addition of the A-D module, the BB-1 or BB-68 can read analog signals. The A-D is a single channel successive approximation device. It can read an analog signal on 5 different scales: <0 to .25v, 0 to .50v, 0 to 2.75v, 0 to 5.00v and 0 to 10.0v.
TS 1000 TS 2068
8 independent relays with LED status indicators and 8 TTL inputs with Schmitt trigger buffers. Single POKE to change/latch each relay. Read all 8 inputs in a single PEEK. More than one BB-1 can be attached to the computer. The BB-1 was used for:
ZX80 ZX81
8 independent relays with LED status indicators and 8 TTL inputs with Schmitt trigger buffers. Single POKE to change/latch each relay. Read all 8 inputs in a single PEEK. More than one BB-1 can be attached to the computer.
TS 2068
Upgraded keyboard with full-size space bar and two shift keys.
TS 1000
Stackable with Sinclair RAM or other M-16 modules to 48K.
ZX80 TS 1000
48K RAM module.
ZX81 TS 1000
Low power, no extra power supply required. Area from 8-16K can be switched out in 2K increments to accommodate memory-mapped peripherals, EPROMs, etc.
TS 1000
Includes RS-232 port.
ZX80 ZX81 TS 1000
Works with any amount of memory on the 1000; with 64K will store 60 screens. Terminal software included. Prints to 2040 or any serial printer via built-in RS-232 port.
ZX81 TS 1000
300 baud. RS-232 port.
TS 2068
Interface to Centronics parallel interface printers. Driver translates Timex/Sinclair code to 80 column ASCII and sends printer via USR calls to simulate LPRINT, LLIST and COPY.
TS 1000
Interface to Centronics parallel interface printers. Driver software supports LPRINT and LLIST. High resolution screen copy program supports multiple printers.
TS 2068
Clock module with battery back up. Logic signal output with LED status indicator can be used to control external devices based on time independent of the computer. DIP switches allow mapping of the module to the 8-10, 10-12, 12-14 or 14-16K areas of memory.
TS 1000 TS 2068
Connect serial devices to the TS 2068. Driver software supports LPRINT and LLIST.
TS 2068
Connect to RS232 printers and terminals. USR calls simulate LPRINT, LLIST and COPY commands.
TS 1000
300 baud terminal program for the 2068, for use with the Byte-Back MD-68 modem.
TS 2068
“Ultimate memory” RAM pack. Battery backup, reset switch, PROM/ROM socket.
TS 1000
64K RAM pack with additional features. 8-16K area selectable in 2K increments. EPROM socket for 2K/4K. Battery backup (6 AA batteries) powers RAM pack and computer for up to 30 minutes. ROM-RAM transfer: copy Timex ROM into the 0-8K area of RAM, flip a switch and operate out of RAM. Switch that only resets 16-32K
TS 1000


  • A Modem for the Timex 1000 or ZX-81
    Review of Byte-Back modem.
  • Add a Full Size Printer to Your System
    Overview of printer interface options for the TS1000/ZX81.
  • An inexpensive computer and interface for research in the behavioral sciences
    The Sinclair ZX81 computer and Byte-Back BB-1 control module are very inexpensive devices that can be used to control equipment in a psychology laboratory. A simple program and description for interfacing the system to a Skinner box are presented.
  • Analog-Digital Converter
    Use with the BB-1 I/O board. Converts at 2.5v and 5v to 8 bit values (0-255).
  • Autotape
  • BB-1 8-Bit Input/Output Module Kit
    Two Intel 8212 8-bit I/O port chips are the heart of the BB-1. Byte-Back’s module is compatible with both ZX and Timex units and neatly uses memory locations 32764 and 32766 to store input and output information.
  • Bits & Bytes
  • Bits and Bytes
  • Bits and Bytes
    Timex Sinclair User has issued its first copy of Timex Sinclair Shopper. It is supposed to come out quarterly. In it there is a subscription form for Timex Sinclair News, the new name for Timex Sinclair User. The new owner of Timex Sinclair User worked with TS User and the former Timex Sinclair User became
  • Bits and Bytes
    Timex Sinclair User is dead; subscriptions will be filled with issues of K-Power.
  • Bits and Bytes
  • Byte Back MD-2 Modem Kit
  • Byte-Back M-64 Memory Expansion
    Review of the RAM pack.
  • Byte-Back Modem
  • Byte-Back Modem Shipments Delayed
    Byte-Back will ship no modems for 4-6 weeks.
  • Byte-Back RS-232 and Tasword Two
  • Compatibility of Machines
    Compatibility of hardware with the TS1500 and TS2068.
  • Dear Editor
    Battery-backed power; errors in printing floating point numbers; using VU-File with Qsave; Sinclair microdrive; overload the TS1000 stack with a simple program; good service from a vendor; thanks to fellow reader; Byte-Back RAM unit.
  • Experimenting With the Byte Back Modem
    How to program modem settings with the TS1000.
  • For Your Support
    Product announcements from G. Russell Electronics, Byte-Back, Variety Sales, Chia-Chi Chao, Larken Electronics, Sams, Fred Nachbaur, Lemke Software Development and E. Arthur Brown.
  • For Your Support
    Hardware and software announcements from many vendors.
  • Highlights of the February Meeting
    Sue Mahoney reported on public library in Sub Oak, NY, that lends TS-1000 computers. Mike Coughlin led discussion on FORTH. Peter Nichols demonstrated Byte-Back modem.
  • Highlights of the September Meeting
    Frank Kaplan from Compusa Corporation demonstrated a prototype of the FDC-101 floppy disk system. Jeff Parker demonstrated the Byte-Back MD1 and MD2 modems.
  • Key Support Operations Will Stay
    Announcements of support from SoftSync, Byte-Back, Microsync Services, Thomas B. Woods, Banta Software, Kopak. Timex will honor warranties.
  • M-16 Memory Module
    Review of the RAM pack.
  • MD-1 Direct-Connect Modem and RS-232 Port
    Review of Byte-Back’s modem.
  • MD-2 Modem
    Review of the Byte-Back modem for the TS1000.
  • Modem and Serial I/O
    Review of Byte-Back MD-1 modem.
  • New Products and Services (Syntax v5 n11)
    Tom Woods sells enhanced Mscript; Byte-Back offers new A/D converter; Tom Bent’s 8K ROM; Powerful Projects with Your Timex/Sinclair; D. Lipinski’s buyer’s guide; Spec-Tax; control your computer with brain waves; green screen monitors.
  • Product News
    Catalogs from Silicon Mountain Computers, Byte-Back, JRC Software. Service manuals from Sams Computerfact. RAMEX discontinues support for 2068 and Millenia K disk systems.
  • Q & A
    Byte-Back UM-64; One Chip Mods; “Delete” machine code.
  • Refining ZCOMM
  • Rumors and More
  • T-S News
    Midwest Timex-Sinclair Computerfest coming. Byte-Back still in business. AN-TO Productions carries line of plastic keyboard overlays for the TS2068, for use with Tasword and MScript. English Micro Connection carries Spectrum games. Zebra Systems selling TS1510 cartridge doc and three cartridges. Applied Sinclair: Subroutines and Programs for the Mathematically Inclined available from Richard Booth. Hacksel Electronics
    Short article about modems available to TS users.
  • Telecommunicating With Your Timex
    Describes accessing various online services with a TS1000 and Byte-Back MD-2 modem.
  • Telecommunication Notes
    Resolving issues with the 2050 modem when used with 2040 printer. Byte-Back keeping up with 2068 modem orders.
  • The Byte-Back MD-68 Modem
  • Timex Tips
    Tips for using the Byte-Back Modem with the TS 2068; calling machine code routines; using the OS-64 cartridge.
  • Tips on Buying Communications Software
    ZCOMM 16/64K, Byte-Back Modem, Spectra Term mentioned.
  • TS-1000 I/O Board
    How a user interfaced his TS 1000 to his train layout with the Byte-Back BB-1 interface board.
  • Turning Your Sinclair-Timex into a Smart Terminal
    Review of Byte-Back MD-1 and MD-2 modems.
  • UM-64 Memory Module
    Using bigger memories creates opportunities for greater losses in a crash. Byte-Back’s battery-back-up scheme cuts this risk. You’ll also get the possibility to have your operating system in RAM (all but the characters), compatibility with the TS1500, switch-selectable banks in the 8-16K area, an EPROM socket you can switch-select into 8-16K, and reasonable documentation from
  • Using the Byte-Back Modem
    The Byte-Back modem is a fine device. It works well and actually does more than advertised. The instruction manual, on the other hand, in its attempt to furnish operating instructions, assembly instructions, and engineering data, is a bit sketchy. A description of the non-standard output on the RS232 board is not given nor is there
  • Vendor Report
    Byte-Back has nearly cleared up its backlog of 2068 modem orders; Ray Kingsley of Sinware believes that some of you may have purchased bootleg copies of an early version of HOT-Z with a bug in it; allegation of Gladstone copying software.
  • Vendor Report and Notes
    Norris Electronics is out of business; Byte-Back memory units might not work with TS2040 printer. Frog Software is distributing May-June issue of Sinclair Computing.
  • What's In Store: Byte-Back Modem (Timex Sinclair 1000/1500)


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