Megatel Quark/100 Specifications download pdf (Page 7)

-------,----------------.--------------------------,

Using

the Megatel

QUARK

with a

television

....

-----------------------------_.------..-.------------------

Using

a commercially available

RF

converter the Megatel

QUARK

can

use

a black

and

white

televsion as a monitor.

As

with

some

of the cheaper composite monitors,

this

method

does

not allow the display of

a

full

80 characters.

Recommended

keyboards

for

the

QUARK

Any

ASCII-encoded

7-

or

8-bit

parallel-output

keyboard

with active-high

DATA

outputs

and

an

active-low

STROBE

output will

work

with the

QUARK.

Note

that

a computer terminal (or

its

equivalent) with a full-duplex

RS-232C

asynchronous

serial

interface

capable of

operating

at

1200

baud can

be

used

instead

of

a monitor and

keyboard.

If

using

a,

terminal simply connect

it

to the 25-pin D-shell connector

at

location

J5

on

the

QTB-3

making

sure

it

is

set at

1200

baud.

Adjacent

to

the 25-pin D-shell

is

a dual

row

26-

pin header

at

location J4. This too

is

the

full

duplex

RS-232C

port.

You

wi

II

notice

that

two

pairs of headers

have

been

wire

wrapped

together.

If

you

are

using a terminal they

may

be

cut only

if

your

terminal supports the protocol involved

(CTS

to

RTS,

DTR

to

DSR).

--_.. -----------------------.------

Required

power

supply for the

QUARK

The

Megatel

QUARK

requires a regulated

+5

and

+12

volt supply with a

common

ground.

These

are the

same

voltages requi red

by

5.25-inch floppy disk drives.

The

current

drawn

by

a

QUARK

128K

SBC

at

+5

volts

is

2A.

The

current requi

red

at

+12

volts

is

about

100mA.

If

this

supply

must

also supply

power

to

operate the floppy disk drives, a monitor,

and

a keyboard, then the

power

requi rements of these devi ces

must

be

a llowed for.

The

color

scheme

for the

DC

power

cable enclosed with the

package

is:

RED

••••••••••••

+5

BLACK

••••••••••

GRD

ORANGE

••

~

••••••

+12

The

-12V

required

by

the

RS-232C

drivers

on

the

QUARK

is

developed

by

an

on-card charge

pump,

so

no

negative

power

supply is necessary.

If

a

QUARK-based

system

fails

to

operate

properly,

the

power supply connections and

voltage levels

in

the system should

be

one

of the

first

things

to

be

checked.

Be

aware

that

reversed

or

incorrect

polarities

may

cause damage

to

the

QUARK

which

is

not covered

by

Megatel's limited warranty.

The

power

supply

chosen

for a system

must

be

able to handle normal current surges.

Some

QUARK

users

have

experienced video display or

CPU

problems because

their

power

supply

was

not

able

to

maintain

+12

and

+5

volts during periods of disk drive

activity.

Since the

QUARK

is

largely

TTL

logic, the

+5V

supply

must

never

fall

below

+4.7SV.

Megatel

Computer

Technologies Toronto,

Canada

Page

H/W-3

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