tc2048.pdf

In the early 80’s the Portuguese market was

flooded with ZX Spectrums: that was the most

popular computer in the market and almost

everyone who owned a computer had a ZX

Spectrum. However, many of the ZX Spectrum

owners weren’t real Sinclair Spectrum owners

but Timex Computer 2048 owners. This machine

was a better Spectrum than the original: to the

less enlightened people it was a Spectrum with a

built-in kempston joystick interface, a much

better keyboard, that was not just superior

ergonomically (mostly because of the real space

bar) but the quality in the mechanics was better.

Even these days most broken Timex keyboards

can be cleaned with alcohol.

This article will explore the machine beyond the

physical differences and exploit some hardware

secrets that made the computer a little

incompatible with the original ZX Spectrum. In

the top Picture can be the screen from the demo

tape that came along with the TC2048.

Timex Computer 2048

Timex Computer 2048 Board

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The Timex Computer 2048 was launched in Portugal and Poland - do not mistake this

computer with the prototype Timex Sinclair 2048 wich was intended to be a 16KB

version of the Timex Sinclar 2068. The Timex Computer 2048 was a ZX Spectrum

clone and featured:

- Z80A CPU clocked at 3.58 MHz

- 48KB of RAM

- 16 KB ROM (Almost the same as the ZX Spectrum)

- Edge connector compatible with the ZX Spectrum, but missing RGB signals,

and the /BE signal.

- RF out connector.

- Ear / Mic Connectors

- Kempston Joystick Connector.

- Extended screen modes when compared with the ZX Spectrum;

- On/Off switch.

On the business scene the TC 2048

was a fairly well-used computer in

Portugal, especially connected to a FDD

3000 system. This system gave 64KB

more to the TC2048 along with 2 disk

drives. It was in fact another machine as

it featured a Z80 of its own. The FDD

gave the TC the ability to run CP/M

which was the most used business-

oriented OS of its time. There was even

a separate, almost professional

keyboard that you could use with it. It

was the game market, though, which

was the real target for the TC2048,

where it was designed to battle hand to

hand with the Spectrum. Many shops

sold it as a natural alternative to the ZX,

‘This is a machine that is not only a toy

but a serious computer’ i can almost

hear the salesman voice saying...

The Machine

As soon as you open the Timex’s box,

you notice the big resemblance with the

ZX Spectrum (it couldn’t be other way,

it’s a clone!). The keys are very similar,

but in the Timex are made of plastic

instead of rubber. You also notice a

joystick connector of the de-facto

standard kempston type. An ON led is

also welcome as is the on/off switch.

Under the hood the differences are even

greater, you get a better quality

computer when compared with the

Sinclair - the most evident is the plastic

Rom differences between the ZX Spectrum and

the Timex Computer 2048.

Address

TC2048 ROM

ZX Spectrum ROM

129A

Call 386E

Call 0C0A,PO-MSG

386E

Out(FF),A

3870

Call 0C0A,PO-MSG

The TC2048 Boot Screen,

exactly the same as the

ZX Spectrum’s one!

3873

RET

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keyboard, which was better not only on

the exterior but on the interior where a

good PCB replaced the fragile

membrane of the Spectrum. The

keyboard PCB uses a mechanism

similar to many calculators where a

special rubber that acted also as spring

made contact between the tracks of the

PCB, thus allowing the keystroke to be

sent to the computer. The composite

output also gave the Timex a more

professional touch, and in this machine

there was no need for a separate

joystick interface, as the kempston

interface was already built in. Plus, the

typical unplug/replug reset procedure

was replaced with a good quality

ON/OFF switch and you could see if

your timex was turned on by the red led

on top instead of the high frequency

whistle you could hear from the ZX

Spectrum’s speaker (many friends of

mine said they couldnt hear a thing from

the speccy, but I swear, I could!). One

thing that you could still complain about

in the machine is the poor quality ink

used on its keyboard- it rubs off with

use! Many of todays 2048’s have the

keywords of some keys worn off,

especially Q,A,O,P keys, who knows

why...

How to use the TC 2048 Modes:

To use the special 2048 modes you

will need to output to port 255, bits

D0, D1 and D2. You can output all 8

values but only 4 will give you some

kind of good result:

- 000 - 8X8 Attributes, just like the

normal ZX Spectrum .

- 001 - Puts video data at 24576

and STTR data on 30720, it still

keeps 8X8 attributes.

- 010 - Multicolour mode, keeps

video data at 16384 and 8X1 color

attributes at address 24576.

- 110 - No colour attributes,

Extended resolution: this mode takes

the video data from 2 different areas:

even columns are taken from

address 16384 and odd columns are

taken from address 24576.

One less known feature of the TC2048

is the Enhanced graphics capabilities.

The TC 2048 used the very same ULA

as the Timex Computer 2068 (Note the

‘Computer’, it’s Timex Computer NOT

Timex Sinclair). This ULA had - besides

all ZX Spectrum modes - some graphics

modes of its own. They were used

widely in conjunction with the FDD 3000

so it could display the 80 character text

that was used by CP/M applications (the

main use of the FDD3000).

Timex Computer 2048 and 2068 ULA.

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Expanding the Timex 2048

What were the Timex Computer 2048’s expansion options ? Well, the TC had the

same edge connector that was present on the ZX Spectrum, although some signals

are unconfirmed on it. It could use most simple ZX Spectrum interfaces and some of

the more complex too, but some, for example the Rotronics Wafadrive, didn’t work

well on it - maybe because of the NEC processor (Z80 Clone) or by some missing

sign or ROM incompatability. The wafadrive can write to wafers but can’t read them

on the TC, so probably some other cpomplex peripherals have the same problem.

Not to worry, though, because as soon as you take a peek at Timex’s own options

there is hardly any need to search in another brand! There are Sound Amplifiers, Disk

interfaces, the famous and rare FDD3000 (which was indeed a true computer of its

own), serial interfaces, and so on. One that I like especially is the 3 part disk

interface, the Timex FDD, wich is compatible with DD 3 1/2 disk drives. Just remove

the incompatible 3 incher that comes along with the unit and plug in the floppy of your

choice (See the pic below).

All in all the Timex Computer 2048 was a very decent and cheap machine that had a

great impact on videogaming in Portugal. It was superior to the ZX Spectrum and it’s

a pity that there were almost no games that took advantage of its superior video

architecture. Timex Portugal was one of the best computer developers of its time and

delivered us some stupendous machines. This model was only exported to Poland,

making it dificult for anyone with no access to the Portuguese or Polish market to get

one. This is definitely a computer that has a place in every serious collector’s

collection.

Special Thanks to

Johny Reed from

http://timex.123go.cx

Jorge Canelhas

Promo Picture of the TC 2048 with the Timex

FDD System.

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