Move #06 31 мая 1997

Железо     Модем

C-DOS modem - Description of the signals C-DOS modem protsedru tested on- The presence of a modem.

               C-DOS MODEM

(C) Ars


    In this short article I will cover
very "sick topic" for discussion and
it is a modem. Primarily on whether the
published scheme modem.

    You can talk a lot on the topic
copyright compliance, rigid
competition and personal gain, etc., but I want to
noted that such issues are resolved
really only the author himself. Verily,
I was alone have a monopoly on
manufacture of modems - is absurd. Scheme
have a sufficient number of people
which may, but do not want to deal with them
production. No selection of users on
servers if they are of course
register online and will abide by
elementary rules of decency (the statute
network because I had still not adopted) is not
scheduled and will not be! Do not take
the following phrase as a joke of the week, but I
ready to publish the scheme C-DOS modem
Minsk Computer zhuranale
"ZX-ELEMENT", the more it will be
be a good incentive to its early
exit.

    Now that is preventing
further development of the network?

    Firstly, people's attitudes segodyashnee
to the Spectrum - I want to say that as
platform, he was not all satisfied with today,
but how ... means of communication available
everything. You may be
radio, fan Dandy,
Finally, just informals - but to work in
Network Zx-Net you can today!

    Second, more "help" in this
had a statement to the effect that future developments Network
 - This is Hayes. I think there is no need
more time to respond to a similar "crisis"
was in other cities, and for example
do not go far - SpbZxNet. That of
this happened: Nothing!, and now
Peter think about how to regain the people
back ... Despite the undoubtedly the best
data, Hayes modem is still not for everyone.
Incidentally, one of the circuits connecting
Hayes'a was published in ONLINE. So
that's up to you, but I would not advise
"... To the ground, then ...".

    The third reason, of course in the absence of
normal programmatic support. All
talk about the new C-DOS'e one
talk and end, no matter where
they did not go. Even undoubtedly the best coder
Minsk - Tankard, can still
say anything definite. Only
program, adapted for today
C-DOS is LaserSquad ... And how would
raised the popularity of network modems
Toys! What can we say about the prospects:
wait and see. So far, support
modem have not primarily
Minsk and other cities. Here is an excerpt from
letter sent to a group of E-Mage of the
Grodno: "We focus not just on
support, and the organization of a global or
absolute (as someone like that) platform
for your modem. The first version will
configured to run in RAM, and then if
everything is O'K, successfully transferred to the ROM
BASIC instead of 128.

    Fourth: to make a popular network
Zx-Net will be able to just you, its users.
The fact that vendors of software for
radio market is absolutely not interested in
development of the network - that they do not
have just the opposite. Of course, the situation
with our network of Minsk, in general unique:
now nick can not go on the market for
novem, everything that has appeared
new in the last five months,
extends only over the network Zx-Net! On
market also learn about updates to software from the network
newspapers :-) So if you want to
network has evolved - do advertise it, so
as you can.

    Fifth: our network today simply
must be able to communicate with other
Network: FIDO and the Internet. But this question
Today I alone can not solve, even though I
try to do everything in my power.
Seek and you do so to try to
together to find some an acceptable
option.

    Finally, the last: if Minsk
Zx-Net and wants to become a normal network, the
it needs a charter network. All, probably already
read the statute Moskow Zx-Net - it is not our
charter, but we can accept it or on its
basis to make a new one. But to create a charter
above all a sysop and users to the network, not
one person ...


    In conclusion, I will give a description of
signals of C-DOS modem protsedurku,
testing the modem.

Port - # EF = 239 =% 11101111-standard port.

In other types of computers are used:
Port - # F3 = 243 =% 11110111 ("Byte")
Port - # 77 = 119 =% 01110111 (GRM)



         bit in out


          7 data data

          6 ring dial

          5 test tube

          4 line test


active signal in = 0
active signal out = 1


    Conclusions in7 and in4 in the scheme of modem
electrically connected to each other, but
more correct to question the status line
to bat 4, and receive data at bit 7.

Checking the modem:


        LD A, # 10

        OUT (# EF), A

        IN A, (# EF)

        AND # 20

        JR Z, not_present

        XOR A

        OUT (# EF), A

        IN A, (# EF)

        AND # 20

        JR NZ, not_present


    In the next issue of MOVE, I (and perhaps
be and not me) continued the theme of C-DOS modem.

    P.S. When the layout is the same number MOVE
it became known that Dr.Li of
Koydanovo (ex-Dzerzhinsk) has developed a new
scheme for C-DOS modem. The scheme was successfully
tested in Minsk lines, but for
long-distance calls has not connect
happened ... The scheme eliminated the main
shortcomings of today's modem, namely:
made a complete galvanic isolation from the
telephone lines, simplified design -
fewer chips, the lack of
transformer and switch (although they are replaced
more expensive optocouplers). In
currently collected experimental
sample, which will be still possible
supplemented by a system of filters that block
display, etc. Of course, these
refinement can be used in
early modern modem. I hasten to answer
the main issue: the quality of communication remains
former ...(!?) I think in the next
Room MOVE, we further explain
you of updates to hardware.