Think #43 03 января 2000

Модем

F.A.Q. - Hayes-up modems.

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From: Kirill Frolov
Subject: FAQ-Haes at Spectrum without glitches.
Date: November 8, 1999 0:21
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     "Hayes on the Spectrum without glitches."

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KF> For the past three months more than I polzuKF> yus 
hayes-compatible modem SportsKF> ter 14400. Of course, this 
modem imeKF> exists a good opportunity. But the main thing is 
KF> access FIDO.No unfortunately not oboshKF> elk with no 
problems. Not seldom nablyudaKF> are strange phenomenon: a 
sudden disruption KF> connection (hangs up) directly during the

KF> exchange, hangs up when dialing, visKF> not (yet not 
disconnected from the whole kompyuKF> ter impossible to do 
anything) ... 

What model year is your Shprot? If 1995go, then you are 
guaranteed zavisony. On what speed lochish COM port in the 
Melon? More than 9600, this program can not * reliably * work.


Power supply (+5 V) to the modem must be submitted directly
from the location of the main board companies, where
it (the food) comes with power supply. :)
Sorry for taftologiyu. :) The wires for this
unusual and should be * minimum * length and cross section
however 1mm.kv! Directly on the slot for a modem unsolder 
electrolytic capacitor (for +5 V, preferably tantalum, such as 
K52-1B. or a series of K53) capacity 47 ... 220mkF.


KF> mode TURBO ...
KF> The modem is connected on Kondratieff scheme.
KF> Used software - Melon 1.80
KF> Until some time, I cheated all
KF> these bugs in the program, explaining all
KF> these things imperfections and krivosKF> Tew Melon 1.80 ...

Sam you a curve. :) Normal softina.
However, only version 1.80 + (it - last) is relieved of most of 
the glitches. 

! Malone to run out of boot'a that before running 
BASIC-programs does: 

====================
LD IY, 23610
RES 4, (IY +1)
====================

If not, then you glyuchnost Mellon guaranteed, especially 
during the dial-up (the program just hangs). 

KF> As a result of prolonged observations
KF> (daily connection), I came to druKF> Goma conclusion.
KF> Almost all glitch to blame
KF> overcritical of the modem
KF> to control signals. This means that
KF> to eliminate glitches potreKF> buetsya withstand any 
temporary paraKF> Meters signals with high accuracy. KF> 
Exactly vyponenie this condition KF> gives the user the 
Spectrum boKF> lshie difficulty (you have a long and KF> hard 
to pick the container). 


And where will you put them already?


KF> The solution is simple: to find
KF> Standard ISA-bus, and according to him sobKF> host signal 
generation circuit upraKF> and implementation. 

Do not need to look for. I think so too
some time ago. Wrong. All your
the problem is likely not caused by a very
correct connection of the modem to a computer or
The problem * very * modem. So, try
do the following:


1. The modem should * always * be connected to
bus companies conductors * minimum * possible length! 10cm - 
this is the maximum! 

2. Between the addresses A8, A9, A10, and modem installed (per 
address) for two series-gate

555 (1533) TL2 (Schmitt trigger). Samuel TL2
(Need one case) in place
close proximity to the modem! In
Ideally - unsolder directly to the slot.

3. "Untie" the data bus and a modem company
with buffer.

==================

So, how to connect the buffer:

                   (File "buf4mod.C")
From the Editor: The file can be found on the same
disk space - it is written immediately after the newspaper.
==================

Meals on ls245 must submit a * short *
wires with a conductor cross-section of at least
0.5mm.kv. / / Feet 10 and 20 (food) hang interlocking ceramic 
capacitor from 0.1mkF up .... :) 

KF> SPEKTRUMISTY COMRADES! If anyone
KF> have this information, share with
KF> all!

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           Regards, Felix.

                   [IZX]
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