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Other Microbee Models

A number of Microbees were released as separate standalone machines, rather than being part of a family or series grouping.

 

TeleTerm

Overview

Name
Category
Release Date
Description
Microbee TeleTerm
TeleTerm
ROM based
Sep 1986
The TeleTerm differs from other Microbees (both earlier and later) in that it is designed as a communications focused desktop appliance, rather than a general purpose personal computer. Marketed as "The Communications Solution", the TeleTerm includes a software package in ROM that provides both ASCII and Videotex terminal functionality, together with a word processor and some basic desktop productivity tools. The TeleTerm is designed specifically to be a cost-effective, convenient and easy to use desktop communications tool.

The machine was first previewed in Online magazine in June 1986 (issue #24) and then announced as being in production by September of that year (issue #27). It sports a new style case and keyboard combination that was originally developed for the Microbee "Delta" project - an unreleased prototype. The new keyboard has a total of 92 keys including a separate numeric keypad and uses a typewriter-paired layout rather than the bit-paired layout of previous models. A new integrated ROM-based software package was developed specifically for the TeleTerm. This package includes:

  • TeleWord - a customised word processor based on Simply Write
  • Telcom - ASCII communications terminal
  • Videotex - Videotex terminal
  • OffSider - a configuration and basic desktop productivity package that includes:
    • File Manager
    • Notepad
    • Phonebook
    • Clock/Calendar
    • Some early promotional material also mentions Calculator functionality as being available but this appears not to have been included in the final product.

Internally, the TeleTerm is based around the same Main and Core boards as the PC85 Premium, but the usual Main board mounted key switches are omitted and a new separate interface board is added instead to support the new keyboard. An internal 300/300 or 1200/75 baud Automodem, together with a telephone handset, is also optionally included.

The TeleTerm has a total of 40KB static RAM fitted, 32K of which is non-volatile (ie battery backed). The non-volatile RAM is mainly used as a file storage system providing a total of 31KB of fast on board storage for holding word processing documents, notes, phonebook etc. These files can also be transferred to/from cassette tape for longer term storage and backup.

 

Details


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TeleTerm Brochure
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TeleTerm Brochure



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TeleTerm Title v1.06
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TeleTerm Menu v1.06



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TeleWord v1.03
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Microbee TeleTerm


CPU
Zilog Z80 @ 3.375MHz
RAM
40KB total SRAM capacity. 32KB of this is mapped between 0x0000 and 0x7FFF and is non-volatile. A rechargable backup battery is fitted as standard. The remaining 8KB is mapped between 0xA000 and 0xBFFF and is volatile (ie, not battery backed).

Uses 5x 8KB CMOS Static RAM (SRAM) chips, eg Hitachi HM6264.
ROM
72KB total capacity, using a combination of 2764 and 27128 EPROMs. Promotional material specifies a total ROM capacity of 64KB, but 72KB appears to have actually been fitted to production machines.

See the Overview section above for details of specific ROM packages that are included with this machine.
Storage
31KB document file storage is available in non-volatile SRAM.

Files stored in SRAM can be moved to/from cassette tape using the OffSider File Manager facility. An external cassette recorder is required for this.
Video
Colour video output is provided as standard via a DB9 socket at the rear. Output is CGA compatible and provides a total of 16 foreground and 16 background colours, including half intensity. The Premium colour palette differs from that provided by the colour add-on boards that can be fitted to Standard models.

Standard monochrome composite video output is also provided via the 5 pin DIN socket at the rear.

Three main display resolutions are available:
  • 64*16 characters.
  • 80*24 characters.
  • 40*24 characters (for Videotex/Viatel).
Uses Synertek 6545 CRT controller.
Graphics
Two graphics modes are available using a Programmable Character Generator SRAM (PCG):
  • Low resolution (LORES):
    • 128*48 pixels on a 64*16 character display.
  • High resolution (HIRES):
    • 512*256 pixels on a 64*16 character display.
    • 640*264 pixels on a 80*24 character display.
PCG RAM capacity is 16KB as standard, but can be expanded to 32KB. The standard 16KB configuration provides a maximum of 1024 unique graphics characters which is sufficient to allow unrestricted HIRES graphics on a 64*16 character display. The expanded 32KB configuration provides for 2048 unique graphics characters so allows unrestricted HIRES graphics on a 80*24 (or 80*25) character display.
Fonts
Dual fonts to support 64*16 and 80*24 character displays. Both fonts support upper and lower case characters (128 characters in total per font).

Uses a single 4KB ROM.
Sound
Internal speaker. Generates sound through software bit bashing.

Unlike other Premium Main board based machines, an optional SN76489AN sound chip cannot be fitted to the TeleTerm because this IC location is repurposed to provide connectivity to the TeleTerm keyboard interface.
Keyboard
92 key QWERTY style with a typewriter-paired layout (ie, not the bit-paired layout that is used for most other Microbees). The keyboard includes a separate numeric keypad, function and direction keys.

A separate circuit board is required to interface the Premium Main board with the new TeleTerm keyboard. This board is mounted internally on a bracket beneath the keyboard.
Serial port
An RS232-like serial port using a DB25 socket is available at the rear if the optional internal Automodem is not fitted. The port is configured as Data Terminal Equipment (DTE) but does not implement all RS232 standard signals and the default factory configuration does not provide negative voltages on output. Nevertheless, it is compatible with many standard RS232 peripherals. Additional components can be fitted to the Premium Main board that will enable negative output voltages on this port, if required.

No external serial port is available on TeleTerms that have the optional internal Automodem fitted. These machines have a blanking plate fitted to the rear panel instead of the usual DB25 serial socket. The single serial port that the Main board provides is used internally instead for connection to the Automodem.
Parallel port
8 bit parallel I/O port via a DB15 socket at the rear.
Expansion interface
An interface to the Z80 bus is available at the rear, but the associated 50 way connector is not fitted as standard. This was available as an option.

The PC85 Premium and TeleTerm (uniquely) have provision for two 50 way expansion interfaces - one on the Premium Main board and one on the Core board. It seems unlikely that the Expansion interface connectors would actually have been fitted to any TeleTerms.
DIN port
A 5 pin multifunction DIN socket at the rear carries:
  • Power input.
  • Composite video output for connection to a video monitor.
  • Tape recorder output for connection to an external recorder's AUX IN/MIC socket.
  • Tape recorder input for connection to an external recorder's EAR (earphone) socket.
System Clock
The master clock runs at 13.5MHz. This provides a 13.5MHz video dot clock and is divided by 4 to provide the 3.375MHz CPU clock.
Real Time Clock
A hardware based battery backed RTC is installed on the Main board.
Modem
An optional Automodem can be fitted internally to provide 300/300 or 1200/75 Baud communications, including auto-dial and auto-answer functionality. If fitted, the modem consumes the single Main board serial port and this is no longer available for external connectivity. A telephone handset is included which plugs into a connector on the left side of the TeleTerm. Phone line connectivity is via a flying lead that emerges from a cutout in the rear panel.

Alternatively, the TeleTerm software supports use of an external modem connected via the serial port.
Case
Delta
Power
10V 1A plugpack

 

Included Software
Version
TeleTerm Kernel in ROM
1.06
TeleWord in ROM
1.03
Telcom in ROM
4.07
Videotex Terminal Emulator in ROM
3.11
TeleTerm OffSider in ROM
1.07
TeleTerm Self-Test in ROM
1.05

Included Documentation
  • TeleTerm Reference Manual

Pricing
$
Microbee TeleTerm incl Automodem
$828.00 (Oct 1986)
Microbee TeleTerm incl Automodem
$999.00 (Jan 1987)
Microbee TeleTerm only (no Automodem)
$699.00 (Apr 1987)

 

Notes


 


256TC (Telecomputer)

Overview

Name
Category
Release Date
Description
Microbee 256TC (Telecomputer)
256TC
Disk based
Mar 1987
The 256TC was unveiled at the PC87 show in Sydney in March 1987, with preview announcements first appearing in Online magazine issues #32 and #33 earlier that same year.

This machine shares the same “Delta” style case as the TeleTerm, but is very different internally and is designed as a traditional general purpose computer rather than a specialised desktop appliance. A completely new 4-layer Main board was developed for the 256TC to provide the first fully functional Microbee on a single PCB. The 256TC does not have a separate Core board.

Despite implementing a completely new board design, functionality remains very similar to the earlier Premium Series. A significant difference though is that the larger 92 key Delta keyboard uses different keyboard scanning hardware and this requires completely different software to drive it. This means that any programs written for earlier Standard or Premium Microbees that contained their own internal keyboard scanning code were likely to be incompatible with the 256TC. Microbee Systems anticipated this problem and included a set of callable routines in the CP/M XBIOS and in Microworld Basic that developers could use to convert their programs into being keyboard hardware independent. Unfortunately, few developers seem to have taken this up and today there are many popular programs in the Microbee catalogue, most notably arcade style games, that will not run successfully on a 256TC.

As the name suggests, the 256TC provides a total of 256KB RAM, 126KB of which is available as a RAM disk under CP/M (drive M:). The machine supports single or dual 3.5" DSDD 80 track floppy drives, each giving a formatted capacity of 776KB (DS80 format). The drives are installed within the 256TC case and face sideways, one drive on each side. When viewed from the front, the right side drive is configured as drive A:.

A new boot ROM was developed for the 256TC that displays a menu system at boot time if there is no bootable floppy disk inserted. This machine was the first Microbee to provide this additional functionality. The boot menu provides access to a self test function, an RTC date/time setup utility and a machine code monitor, as well as allowing for a subsequent boot from floppy disk, once inserted.

 

Details


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256TC Brochure
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256TC Advert



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256TC Brochure
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256TC Boot ROM Menu



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Simply Write v2.05
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Microbee 256TC


CPU
Zilog Z80 @ 3.375MHz
RAM
256KB total capacity.

Uses Dynamic RAM (DRAM) with 8x 41256 RAM ICs.
ROM
16KB Boot/Monitor ROM (a single 27128 EPROM).
Storage
Either:
  • Single or dual 3.5" DSDD 80 track floppy drives, or
  • Cassette tape via an external recorder
Video
Colour video output is provided as standard via a DB9 socket at the rear. Output is CGA compatible and provides a total of 16 foreground and 16 background colours, including half intensity. The Premium colour palette is used, which differs from that provided by the colour add-on boards that can be fitted to Standard models.

Standard monochrome composite video output is also provided via the 5 pin DIN socket at the rear.

Three main display resolutions are available:
  • 64*16 characters.
  • 80*24 characters.
  • 40*24 characters (for Videotex/Viatel).
Uses Synertek 6545 CRT controller.
Graphics
Two graphics modes are available using a Programmable Character Generator SRAM (PCG):
  • Low resolution (LORES):
    • 128*48 pixels on a 64*16 character display.
  • High resolution (HIRES):
    • 512*256 pixels on a 64*16 character display.
    • 640*264 pixels on a 80*24 character display.
PCG RAM capacity is 16KB as standard, but can be expanded to 32KB. The standard 16KB configuration provides a maximum of 1024 unique graphics characters which is sufficient to allow unrestricted HIRES graphics on a 64*16 character display. The expanded 32KB configuration provides for 2048 unique graphics characters so allows unrestricted HIRES graphics on a 80*24 (or 80*25) character display.
Fonts
Dual fonts to support 64*16 and 80*24 character displays. Both fonts support upper and lower case characters (128 characters in total per font).

The standard configuration uses a single 4KB ROM. This can be upgraded to an 8KB or 16KB ROM to support other languages.
Sound
Internal speaker. Generates sound through software bit bashing.

An optional SN76489AN sound chip can also be installed on the Main board.
Keyboard
92 key QWERTY style with a typewriter-paired layout (ie, not the bit-paired layout that is used for most other Microbees). The keyboard includes a separate numeric keypad, function and direction keys.

The keyboard is driven by an M3870 microprocessor.

An external serial keyboard is also supported. If fitted, this does not use the M3870 microprocessor.
Serial port
An RS232-like serial port using a DB25 socket at the rear. The port is configured as Data Terminal Equipment (DTE) but does not implement all RS232 standard signals and the default factory configuration does not provide negative voltages on output. Nevertheless, it is compatible with many standard RS232 peripherals.

Additional components can be fitted to the Main board that will enable negative output voltages on this port, if required.

Microworld Basic uses this port to provide 300 and 1200 baud serial communications through software bit bashing.
Parallel port
8 bit parallel I/O port via a DB15 socket at the rear.
Expansion interface
An interface to the Z80 bus is available on the Main board, but the associated 50 way connector is not fitted as standard. Unlike other Microbees, the 50 way interface is located near the centre of the Main board rather than being adjacent to the rear panel.
DIN port
A 5 pin multifunction DIN socket at the rear carries:
  • Power input.
  • Composite video output for connection to a video monitor.
  • Tape recorder output for connection to an external recorder's AUX IN/MIC socket.
  • Tape recorder input for connection to an external recorder's EAR (earphone) socket.
System Clock
The master clock runs at 13.5MHz. This provides a 13.5MHz video dot clock and is divided by 4 to provide the 3.375MHz CPU clock.
Real Time Clock
A hardware based battery backed RTC is installed on the Main board.
Modem
The original 256TC release did not offer a built in modem. An external modem can be connected via the Serial port instead.

It appears that an internal modem was made available at a later stage (see Online #35). Specifications of the internal modem are not known, nor is it clear where/how this was fitted, however advertising infers that the built in modem was only available in a single drive configuration so it was possibly installed on the left side of the case where drive B: would otherwise fit. As with the TeleTerm, it probably also consumed the single Serial port, making it unavailable for connection of external peripherals.
Case
Delta
Power
10V 1.5A plugpack

 

Included Software
Version
Boot/Monitor in ROM
1.15 or 1.20
Simply Write
2.05 or 3.02 or 3.03
Telcom
2.4 or 2.41 or 3.00
Videotex
1.43 or 1.53

Included Documentation
  • 256TC Basic Manual Vol 1
  • 256TC Basic Manual Vol 2
  • 256TC Basic Manual Vol 3
  • 256TC CP/M Reference Manual
  • 256TC Simply Write Manual
  • 256TC System Software Manual
  • 256TC Telcom Manual
  • 256TC Videotex Manual
  • 256TC Technical Reference Manual
  • Other manuals that were potentially included in later stages:
    • 256TC Quick Start
    • 256TC Learning the 256TC
    • 256TC Shell Reference Manual

Pricing
$
Microbee 256TC with single 3.5" floppy drive
$999.00 (Apr 1987)
Microbee 256TC with dual 3.5" floppy drives
$1299.00 (Apr 1987)
Microbee 256TC with single 3.5" floppy drive & built in modem
$1095.00 (Summer 1988)

 

Notes

  • The RTC uses a rechargeable 3.6v NiCd battery to maintain the clock when the machine is shutdown. This battery is mounted on the Main board as is often found to have leaked over the years, causing significant damage to both the board and its components. Owners of any original machines today would be well advised to remove or replace this battery ASAP.
  • Online #34 includes a review article for the 256TC that states that surface-mount technology is used to enable this machine's portability. This is not correct - the 256TC uses only standard through-hole components.