Iron - connecting the "Hayes" modem to the Spectrum.

Connecting internal Hayes-compatible  
         our modems to the Spectrum.         
------------------------------------------
 First, I want to say a few words about
water of all of the following. Basically this
scheme  already  has been published more than once, but... But
after all, not everyone has a St. Petersburg electronic
this newspaperZX-News,in the 15th issue of which
there was a similar article. And especially not
each   has   access to  echo conference
ZX.SPECTRUM  in  Fidonet network. And therefore we
took the liberty to bring this to you
material, dear readers. Moreover,
here  well  we  we'll tell you about thosesubtleties
connections that we ourselves encountered. 
 COPYRIGHT to the controller circuit belongs to
lives Mikhail Kondratiev.The author of the article, under
impression from which  this -
Igor Gruzdev.                            
 In the very first lines I want to once again dispel
the myth that it is normal hayes-compatible
The modem can only be connected to Scorpio.
Nothing   like that!  Just on the system
the Scorpio connector has already brought out all the necessary
dim signals, but the owners, for example,
Pentagons  will have to you will have to stretch them yourself.
Moreover, it is still unknown who was so lucky -
hey, owners of Scorpio or Pentagon -
"Pentagonists" do not need  to assemble a circuit,
blocking internal computer ports.
Yes  and  matchinginternal and external
signals /NMI in Scorpio there are a few
th  unsuccessfully (by  extreme  at least for this
connection diagrams).                       
  So, fewer words,  closer  to the point. For
implementation of  internal controller (!!!)
HAYES-compatible modem  you will need
three microcircuits and 8-10 resistors. Micro-
circuits: DD1 - LL1, DD2 - LN1, DDZ - TM2. Se-
any ria, even the 1533rd, even the 555th, prin-
this has no fundamental significance. Resis-
tori any nominal value in the range from 1 to
15 kOhm.                                   
                                          

  As you can see, the scheme is quite simple. Cle-
on the other side are the names of the signals and
numbers  contacts  (A  - top row, B -
bottom) for Scorpio, on the right - Hayes-
compatiblemodem. To the 1st trigger input
(DDЗ)  a 1 KOhm resistor should be applied
+5V for more reliable operation of the circuit. For
powering the microcircuits  to  their 14th pin
it is necessary to apply +5V, and to the 7th - ground.  
  As  can be seen from the diagram, the controller is
does decryption using just one address -
new signal - A4, and meanwhile, its full
address  - #xEF.  Therefore, if you have Speed
pion or any other computer that has
go when decrypting internal ports, do not
 signal is analyzed  A4, then you need more
assemble  and signal generation circuit  signal
/IORQGE, which you can find in the same
issue, in the article about connecting C-DOS mode-
ma.  The input signals for this circuit are
output:/IORQ andA4,output - /IORQGE.      
  Now about what the layout will look like
soldering  slot modem and system connector
computer (contact numbers are given for Speed
peony:  A - top, B - bottom: on the modem: top
- the top part of the board where everything is located
microcircuits,  numbering slot contacts
starts from the phone jack side
line and further along the modem):         
                                          
     Scorpio  Modem             
   ┌------┬---┐   ┌---┬------┐         
   │A 8  │A26│----> │A31│ A 0  │         
   │A 9  │B27│----> │A30│ A 1  │         
   │A10  │A27│----> │A29│ A 2  │         
   │D 0  │A6 │----> │A9 │ D 0  │         
   │D 1   │A7 │----> │A8 │ D 1  │         
   │D 2   │A8 │----> │A7 │ D 2  │         
   │D 3   │A11│----> │A6 │ D 3  │         
   │D 4   │A12│----> │A5 │ D 4  │         
   │D 5   │A10│----> │A4 │ D 5  │         
   │D 6   │A9 │----> │A3 │ D 6  │         
   │D 7   │A3 │----> │A2 │ D 7  │         
   │      │   │      │A28│ A 3  │ -┐      
   │      │   │      │A27│ A 4  │  │ на   
   │      │   │      │A26│ A 5  │  │ +5В  
   │      │   │      │A25│ A 6  │  │через 
   │      │   │      │A24│ A 7  │  │3-10К 
   │      │   │      │A23│ A 8  │  │      
   │      │   │      │A22│ A 9  │ -┘      
   │      │ │      │A21│ A10  │ -┐  на  
   │      │   │      │A20│ A11  │ -┘ землю
   │      │   │      │A11│ AEN  │ на землю
   │ +5v  │В3 │----> │В3 │ +5v  │         
-->│ +12v │В17│----> │В9 │ +12v │         
-->│ -12v │A16│----> │В7 │ -12v │         
-->│ -5V  │A18│----> │В5 │ -5v  │         
   │ GND  │A30│----> │В1 │ GND  │         
   │ GND  │В30│----> │В31│ GND  │         
(*)│/IORQG│В13│-│н │ │   │      │         
   │/RESET│В20│-│а │ │   │      │         
   │ /RD  │A18│-│  │ │   │      │        
   │ A4   │В24│-│п │ │   │      │         
   │/IORQ │A17│-│л │-│В2 │ RESET│         
   │ /WR  │A19│-│а │-│В14│ IOR  │         
   │ A11  │В28│-│т │-│В13│ IOW  │         
   │ /NMI │A14│-│у │-│В24│ IORQ4│         
   └------┴---┘      └---┴------┘         
    сигнал                сигнал          
                                          
Обозначения слева:                       
-->  -  supply the signal to the system connector
 yom.                              
(*)  -  only  for computers in which
 needed  block internal
 ports (signal /IORQGE).           
                                          
  Itself  modem need  set toCOM1,what
corresponds to the address #3F8  and  query  on
interruptIORQ4. About what kind of jumper-
We can do this, read the instructions
according to your modem.                         
                                          
  Well here,  now all that's left to do is
a little - slightly modify your computer
yuter.                                     
  Firstly. We must  implement normal
coordination signals  /NMI, received from
system  connector (if you have
it is not present - output)  and  from the Magic circuit
buttons.  This is done by  by adding everything
only one chip 5SSLI1 (or any
other  series). To do this, about the processor
cut the path leading to his 17th
contact,  and insert a logical
element  "AND" (K5SSLI1), to the second input
which supply the signal /NMI with system-
th connector. The changes will look like this:
in the following way:                           
                                          
                     ┌-------             
                     │                    
                   17│                    
  ------┬---х-----┬--┤ Z80                
        │ 1┌---┐ │ │                    
        └--┤&  │3 │ │                    
  /NMI  2│ ├--┘ │                    
  ---------┤ │  └------              
           └---┘                          
                                          
 Secondly. If  you do not have the Pentagon and
Pros, andwhen decrypting internal ports
does not  signal A4 (for example,
in  Scorpio  controller   the modem will
conflict with the internal port #FF), then
you need to take care ofso that  sign-
signal to the system connector /IORQGE. Ec-
If  you  you  it is not there, then, again, read
about this in the article about connecting C-DOS mode-
ma - you will need to add everything to the board -
there is only one resistor.                    
  Thirdly. Negative voltages for
modem  One  of  the most painful questions,
because if on the connector of your modem
these contacts are involved, then submit
on  their corresponding voltage  MANDATORY
BODY  !!!  That is, for example, if the modem
enabled  contacts B5 (-5v) and  B7
(-12v), then it is necessary to supply these
voltage. If you have an IBM pi block
tania,  then  all these voltages are there, and
you  can  not worry.               
 Fourth.  The most painful question
- bug fix in ROM. Like probably
many  know, in the standard ROM-48 co-
holds gross mistake  in the procedure
processing  non-maskable  interrupts. By
address #006D instead of the command JR Z,#70 (codes
#28 #01),  is located  command  JR NZ,#70
(codes #20  #01). In theory, this should work
So like this: when a non-maskable
The processor  starts the procedure
address  #66, which takes the vector (address)
procedures  processing from cell #5CB0: if
in  this cell is 0, i.e. the vector is not defined,
then control returns to the interrupted process
gram: if the vector is defined, then
A transition is made through it. As a result
errors, transition to the vector is carried out
namely  then,  when it is not defined, i.e.
equals  0.  In as a result, the computer resets
is happening.                                  
  To our great regret, there is only
One way to fix this error is to re-
to flash ROM-48. However, some programs
we  do not use non-maskable interrupt
from  modem, but that’s why they are like
It seems that "do not use to the fullest" extent -
ku all the features of hayes-compatible modes
mov. Therefore, our advice to you: try
find  possibility  and reflash your
ROM. Although, if you are a Scorpio owner,
with  version  shadow monitor 2.95 and higher,
then this error has already been fixed.       
                                          
                                          
  Well here,  we connected the modem, but how did
first check it out. To do this, get
some terminal program that
paradise works with this implementation of control
Lera, and run it. For example, a terminal
under  IS-DOS,  written  by ourselves Mikhail
Kondratiev.                             
  For  checking the connection between the computer and
modem, turn on the echo mode in the modem (re-
give  the modem command ATE1),although, usually,
in  most  modems this mode is enabled
by  by default. In this case, the modem will age
protect every byte sent to it. If the connection
without failures, then on the screen every input
by you the symbol will be duplicated (one with
keyboard, the second - echo from the modem). Next
blowingalso remember that in some terms
cash  (for example,  in  terminal  by Alex
Globa  under  IS-DOS) output mode disabled
input characters, and all characters that
displayed on the screen - modem echo. There's more here
easier   - if, say, you pressed a key
"I", and the letter Q appeared, then this is incorrect
correct, but if I - everything is fine.     
  Here,  in principle, that's all. Now for you
doors are open  to  fascinating world BBS,
electronic networks and other wonders of technology
gii. You can  download  from your friend
IBM's agent any file. You will be able to get
access  to  IBM's BBS, and if you're lucky,
then  and to the network nodes FidoNet.               
                                          
 And certainly you will get access to the
currently located in Samara Spectrum Network on
hayes-compatible modems.                
                                          
  And finally, for those who are interested,
how the controller works.                  
  Modem ports are sampled when
A4=0,  in this case, the signals A8-A10 set one
from  seven modem registers. But... But how
as can be seen from the diagram, this also takes part
one more  address signal -  A11. It is not
participates  directly in  modem sampling, it
only sets interrupt key states,
assembled  based on the DDZ trigger. When
write to any register of the modem, the key is received
Shows the state of line A11. And why all this?
- you ask.  But why. When closed
key  (5th pin  DDЗ =  1), at the output
controller - computer input signal /NMI
always  equal to  1,  regardless of state
modem  signal  IORQ4.  That is, pulses
interrupt request generated by the modem,
will never get to the computer.          
  When  records  in register  at A11=0 key 
the signal state opens and
direct  depends on IORQ4. When RESETe computer
The yuter key closes again.             
  Thus,  addresses of the modem registers
determined by the mask:                      
F E D C B A 9 8 7 6 5 4 3 2 1 0           
-------------------------------           
х x x x 1 r r r 1 1 1 0 1 1 1 1 - 0EF-7EF 
х x x x 0 r r r 1 1 1 0 1 1 1 1 - 8EF-FEF 
                                          
х - the state is not taken into account.             
r  - the corresponding digit of the three-bit    
register numbers of the modem.                   
                                          
  Here.  That's it now. Collect, connect
tea and enjoy.                    
                         (C) Evgeniy Milun
MUSIC VU: MARKET SOFT                    
-═════════════ -
 * * *