City #19 14 июля 1999

Железо

Iron - articles on pazpabotannomu fipmoy X-TRADE XTR modem.

--------------------------------------------------
                 PLANET SHELEZYAKA
--------------------------------------------------

  (C) V. Kazakov


  Your attention is invited article from the St. Petersburg 
newspaper network ZX-News, devoted to technology developed by 
X-TRADE modem. The same one that I ordered from Nemo three 
weeks ago, and which still continue to expect it with 
impatience, -]. 

  Article published unabridged.



   (C) <LD> X-TRADE GROUP


                     XTR-MODEM


                 ----- ---- IRON

    Initially we planned to improve
VICOMM and make it as cheap. Alas!
no half-measures have failed, the original
handicap VICOMMa not allowed to implement all
ideas, namely: the ability to automatically (without
button) off-hook, call control and Employment
line. All this provides unprecedented opportunities
such as: pulse and tone dialing
opportunity to redial, caller ID,
recruited from a parallel phone
automatic detection of caller ID
subscriber (AON), and as a modem and improved service
and improving the quality of reception / transmission.

    I do not do nothing to stop the incidental function of
modem - caller ID, because AON think certainly useful and
the feature in the modem.

    Therefore software compatibility with VICOMMom
was lost, but not completely.

    When communicating on the network process is as follows
way: you turn on the machine, load a program,
turn off the monitor, unplug the phone, not to
rang out, and go to bed. And in the morning over a cup of tea
and a plate of semolina, you're flipping through ascended
message.

    Has an internal modem (it's cheaper
structure) - it is stuck in the slot SCORPION / KAY and
its connection is not accompanied by heating
soldering iron. Connecting to other
SPECTRUM-compatible machines escort
the inclusion of a soldering iron and use thereof in accordance 
with instructions.


    The modem is galvanically isolated from the line
(Breakdown voltage of 1.5 Kv). Decoupling is done
through the optocoupler, and not a transformer, as in
VICOMMe, which again reduces the cost of construction and
reduces its size.

    Met all the standards for terminal
telephone network (maximum 250 uA leakage,
maximum voltage - 220 V, maximum current -
100 mA).

    When the computer is off when the modem is not
enjoy, as well as by pressing RESET, the modem
off line and does not have it any
influence.

    The signal of the modem has a frequency band
to transfer more than 20 kHz, at the reception - more than 10 
kHz, more than enough to share for 3200 baud

(If the line and the station will allow). Maximum
Test the speed - 3900 baud, the results
encouraging.

    An important detail: the realized hardware
support exchange with a modem in the face of the gating
process chosen kvartsovannoy frequency
through the signal WAIT. The idea of ​​this - the program
written under the clock speed CPU SPECCY not lower
say, 3.2 MHz, and all machines with greater frequency
retarding to the desired. Unfortunately, there are
limit - no more than 7.0 MHz (typical
Turbo mode).

    It is very convenient - the quality of communication does 
not depend on makeshift machines and do not use the button

TURBO, everything is working, including the CONNECT
SCORPION-PENTAGON.

    Possible to transmit an analogue signal in line with
quantization of 16 levels by
PWM modulation sampling rate up to 23 kHz
(Voice capabilities AON RUSS-16 and above, as well as
DIGITAL STUDIO).

    Structurally, the device is a
PCB size 75 * 70 mm and contains a connector
in the form of slots SCORPION / KAY and telephone jack
line. Current consumption from the power source SPECCY
about 100 mA. +12 V is not required.


                  ----- SOFT ----

    While the modem into production, we adapt
existing terminal program, as well as write
new. Already altered MODEM 3.6 and write a program
AON.

    Peredelany MODEM 3.6 can be used
Communication XTR-VICOMM.

    This project is supported and the program OMEGA GROUP
Macro-Modem will be adapted to the XTR.

    We are confident that XTR fully replace all
VICOMMy and will become the standard platform
ZX-SPECTRUM.


              to be continued ...