ZX + FIDO

(also went to NETMAIL)

Hello, Eudgine!

04 Jul 98 Eudgine Palenock, hoping that Everyone would read, wrote:

EP> What do you need to put on the ZX-Spectrum-512Kb in order to work
EP> with Fido?

You need to pull it from the ZX_Server, 2:465/98.17; or with SpaceServer,
2:5050/33.2 Melon 1.79a package. (command to the server - in the Subj field:
to begin with %LIST, then - the required alias).
In the package there is a terminal with a mailer, a dock, a circuit and Hobet 1.99.

EP> Answers like 'hang up HAYES' are never ceaseless. You need a specific
EP> diagram for connecting it,

There are several schemes for connecting a HAYES modem to a Specky.

If you have SOPP (or KAI?), then you can buy a SMUK, the
internal haes just plugs in there. In other computers, or if
you don’t have enough money for SMUK, you can connect using two
(Shepelevskaya circuit, without support for interruptions) or three
(Kondratievskaya, for Melon you don’t even need to change the ROM yet)
fine logic packages.

If the modem is external, then it’s more difficult, you need a serial
port. For Penta (and other computers) there is a comp port scheme by
VIC, or you can hook up a PC via a multicard...

EP> what models of modems can be installed on the ZX, and what kind

Modems are more convenient internal, almost any (the main thing is not
Plug'n'Play only, the presence of V42bis is VERY desirable) with
speeds from 2400 to 33600 bps. Yes, bosses are already reluctant to take points from2400, but it is very cheap and, if
the line is good, it is quite enough.

EP> programs besides ZED need
EP> to be found... Soap, plz.

Or maybe someone else is interested?!

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Here is M. Kondratiev’s diagram. The difference from Shepelevskaya, as you can see,
is in the use of the IRQ4 signal of the modem to interrupt the Z80.
In Spec's ROM, in BASIC48, it is necessary to correct the
NMI processing error. In cell 006DH, replace code 20H with 28H. (I have to rewrite it; I did it a long time ago.)

If you want to keep the MAGIC button working, then you need to send NMI signals to the
Z80 from this circuit and from the flop controller
through an additional one. element LI1, or better (simpler) - two diodes and
resistor.

K555LL1
┌─┐
/RD ────────┤1│
┌─┐ ┌──┤ ├──── IOR (B14)
A4 ─┤1│ │ └─┘
/IORQ─┤ ├─┤ ┌─┐
└─┘ └──┤1│
/WR ────────┤ ├─┬── IOW (B13)
└─┘ │
┌──────┘ K555TM2
│ ┌─┬─┐
│+5v 1─╪R│Q├5───────┐
│ ├─┤ │ │
└────3─┤C│ │ │
A11 ──────────2─┤D│ │ │
├─┤ │ │
/RESET──┬──────4─╪S│ │ │
│ └─┴─┘ │
│ ┌─┐ │
└─┤1╪── RESDRW (B2) │
└─┘ │
K555LH1 ┌─────────────┘
│┌─┐
┌─┐ └─┤1├── /NMI
IRQ4 (B24) ─┤1╪┤├┬┤ │
└─┘ │└─┘4.7K
2000pF └──══─+5V

───┐ ┌─── MODEM
A8 │───│A0 (A31)
K A9 │───│A1 (A30)
O A10│───│A2 (A29)
M │ │
P D0-D7│═══│D0-D7 (A9)-(A2)
───────┘ │
│
to +5v ═ 10K ═│A3-A10 (A28)-(A21)
GND ──│AEN (A11)

Power supply to the modem:
+5v - B3, B29
-5v - B5
-12v - B7
+12v - B9
GND - B1, B10, B31
Which of them are needed - see along the paths to the ISA connector of the modem.

M.s.K555LL1, 1/2 K555TM2 and two inverters K555LH1 are used.
(I try to use episode 1533.)

Good bye.
With great respect Roman Milukow
-------------------------------------------------------------

All the best.
With respect Roman.