Hayes Modem [01/02]

A big greeting to you, dear Vasya!

On a frosty day on May 03, 1997, at 21:40,
Vasya Noskov wrote a letter to All:

VN> A sincere request to everyone who knows
VN> anything about connecting the subject to
VN> SPECTRUM (equipment and programs).

There is a circuit developed Misha Kondratyev.
its advantages: simple + there is software (terminal in
IS-DOS)
its disadvantages: many hayes-compatible modems
do not work with it.

there is SMUC by Scorpion. drawback - there is no
software, but it will be soon...

I think many will be interested, and therefore I’m throwing it into the echo...

from the ZXNEWS newspaper, issue 15:

=== cut ===

┌───────────┐
│ Iron │▒
└───────────┘▒
▒▒▒▒▒▒▒▒▒▒▒▒▒

(c) Igor Gruzdev
──────────────────────────

Hello, ZX-Spectrum fan's!

When the lion's cage
says "Donkey" - no
believe your eyes.
(K. Prutkov)

I, as one of the pioneers (isn’t it, a little immodest, but I hope you
forgive me) of the movement in FIDO from Spectrum on a normal Hayes-compatible modem,
was recently quite surprised. And here's what.

As I found out, in the St. Petersburg Spectrum
movement there is an opinion thatthe combination
spectrum + modem is only possible if you have a ZS-256. Moreover, this opinion was strengthened even after the hard drive controller and a slot for connecting external peripherals compatible with ibm equipment, developed by the Scorpion company under the leadership of Mr. Zonov, appeared on the market. But what about, you ask, the Pentagons, Leningrads, Kais?

Let's leave aside the issues of connecting a hard drive and a blaster to _not_ Scorpio and consider the most pressing
problem - what to do if someone wanted to connect an internal modem to 2400
(or maybe more) and use huge and interesting possibilities for organizing Fidonet, if there is only Pentagon
128?

I will give the answer - take a soldering iron in your hands and
connect. And rejoice if you have a Pentagon, because the circuit will be just a little shorter than on Scorpio, since there is no need to block additional ports (Scorpio's destiny), you don't have to worry about the subsequent operation of the Magic button.

Although, for those who especially love this “device”,
it is possible to implement the operation of the Magic button on the Pentagon, but that’s who does he use it?

So, let's consider the scheme for connecting Hayes to Scorpio. (Although this name of the modem does not entirely correspond to reality, it would be more correctsay "ha-
yes-compatible modem", but to save
space we will accept this terminology)

The circuit is edited by Boris Sokol,
the copyright for the circuit design
belongs to Michael Kondratyev
(2:5030/362.1).

Modem matching board with Scorpion

(Fig 1)

B18/RD LL1 12┌──┐┌──────────>IOR/B14
>────────────────┤1 ├┘ ┌────────>IOW/B13
13│ │11│
A24/A4 9┌──┐8 ┌─┤ │ │
>────────┤1 ├──┤ └──┘ │
B17/IORQ 10│ │ │ LL1 │
>────────┤ │ │1┌──┐3 │
└──┘ └─┤1 ├──┤ TM2
B19/WR LL1 2│ │ │ 1┌─┬──┐
>────────────────┤ │ │ ─or│ │
A28/A11 └──┘ │ 2├─┤ │5
>> 3├─┤ │ │
└────/C│ │ │
A20/RESET 4├─┤ │ │
>────────┬──────────────────oS│ │ │
│ └─┴──┘ │
│ ┌──────────────────┘
│ ┌──┐ │
└─┤1 o───│────────────>RESET/B2
3│ │4 │
└──┘ │ ┌──────>IORQ4/B24
LH1 │ │ 1┌──┐
│ └──│1 o──┐
│ LH1 │ │2 │
│ └──┘ │
│┌────────────┘
│ │ 4┌──┐
│ └──│ │6 LL1
│ 5│1 │──┐
└────│ │ │
└──┘ │
b23/NMI>───────────────────────┘

>- contact number on the system bus/
/signal name
-> name signal/ connectors of the modem

chips: 555LL1, 555LH1,555TM2
pins: 7 - ground
chips: 14 - + 5 v

connect capacitors:
to 7 and 14 legs of LL1 m TM2
to +12v modem capacity: 0.01-0.1 uF
------------------------------------------
Refinement of the SCORPIO circuit

┌────┐
cut │ │
\ 6│D55 │
>──┬──x───┬┤ │
│ ┌──┐3││ │
│1│ ├─┘│ │
A4 └─┤ │ └────┘
>────┤2 │
to Z80└──┘ DD 555LI1
(Fig. 2)

cut ┌────┐34
17│ │->A4 m/s 555LI1
>──┬──x───┬┤ │ solder on the next-
│ ┌──┐6││Z80 │ higher, next to
│4│ ├─┘│ │ system
└─┤ │ │ │ connector
<───────┤5 │ │ │
NMI/b23 └──┘ └────┘
to the system connector
(Figure 3)

------------------------------------------
scorpion modem
┌──────┬───┐ ┌───┬──────┐
│A 8 │b26│----> │a31│ A 0 │
│A 9 │a27│----> │a30│ A 1 │
│A10 │b27│----> │a29│ A 2│
│D 0 │b6 │----> │a9 │ D 0 │
│D 1 │b7 │----> │a8 │ D 1 │
│D 2 │b8 │----> ├a7 │ D 2 │
│D 3 │b11│----> │a6 │ D 3 │
│D 4 │b12│----> │a5 │ D 4 │
│D 5 │b10│----> │a4 │ D 5 │
│D 6 │b9 │----> │a3 │ D 6 │
│D 7 │b3 │----> │a2 │ D 7 │
│ │ │ │a28│ A 3 │ -┐
│ │ │ │a27│ A 4 │ │ HА
│ │ │ │a26│ A 5 │ │+5v
│ │ │ │a25│ A 6 │ │чеpез
│ │ │ │a24│ A 7 │ │3-10k
│ │ │ │a23│ A 8 │ │
│ │ │ │a22│ A 9 │ │
│ │ │ │a21│ A10 │ -┘
│ │ │ │a11│ AEN │ на землю
│ +5v │a3 │----> │b3 │ +5v │
-->│ +12v │a17│----> │b9 │ +12v │
-->│ -12v │a14│----> │b7 │ -12v │
-->│ -5V │a16│----> │b5 │ -5v │
│ GND │a30│----> │b1 │ GND │
│ GND │b30│----> │b31│ GND │
│RESET │a20│- на │ │ │
│ RD │b18│- │ │ │
│ A4 │a24│- п │ │ │
│ IORQ │b17│- л -│b2 │ RESET│
│ WR │b19│- а -│b14│ IOR │
│ A11 │a28│- т -│b13│ IOW │
-->│ NMI │b23│- y -│b24│ IORQ4│
└──────┴───┘ └───┴──────┘
сигнал сигнал

---> подвести сигнал на
системнyю шинy

Кабель, соединяющий системныйborrow
Scorpion'a with a compatibility board with a spare-
nym on it borrowed modem (slot), should
be no longer than 25 cm. group.