Entex planned to introduce a computer add-on for the VCS, called the
Piggyback, at about the same time that Atari was promising their
"Graduate" keyboard. The name is slightly misleading because, unlike
the Atari add-on, the unit does not rest on top of the 2600. It is
connected by means of an "umbilical cord" and actually sat in front
of the 2600 machine.
The Piggyback's advantage over its counterparts (Expander, Graduate
and CompuMate) was its full-stroke keyboard, which had a professional
look and a nice, typewriter-style touch. (Atari's keys were made of
elastometric rubber and more closely resembled the keys of a calculator
than those of a typewriter.)
Entex's computer was not without its drawbacks, however. Detractors
pointed out that the Piggyback had less memory than the Atari (3K vs. 8K),
its built-in BASIC language was somewhat restricted, and it did not provide
an interface to use a tape recorder to load and save programs (all software
programs were to be in easy-to-load cartridge form. However, an expansion
module was planned to take care of all these limiatations.
In trade shows where it was demoed, the Piggyback was lauded by the
press for its inferior graphics compared to the Graduate. Both
its resolution and sprite capabilities of the Entex machine paled
in comparison with the Atari.
The Piggyback was slated to retail for $130 and the expansion module
$60, before Entex canned the project altogether.
* Z-80A Microprocessor.
* 2K Bytes User Accessible RAM (expandable to 16K).
* 1K Byte Video RAM.
* 8K Bytes Built-in BASIC.
* 128 Characters and a 32X16 character display.
* 16K Memory Expansion Cartridge.
* Peripheral Expansion Module with RS-232.
* Disk Drive Controller
* Retail Demo Cartridge
* Home Finance
* Beginning Math
* Speed Reading
* Word Games
* Sports Statistics
* Computer Typing
* BASIC Programming
* Beginning Algebra
* Spelling 1
* Number Games