›               o=o=o=o=o=››             Modern Modems›            by Alan Sharkis›› When I started modeming with my Atari› system,  it  was  with an Avatex 1200› baud modem.  There was nothing  fancy› about  it.   It might have taken me a› few hours of exploration to find  out› what kind of configuring was possible› on it, but basically, it  worked  out› of the box.  A bit later on, I bought› a 2400  baud,  error  correcting  and› compressing modem. It was a Practical› Peripherals   v.42bis.   Once  again,› there wasn't much that had to be done› to it to make it work.  When I bought› my first PC, a '286 machine, I simply› added some cables and an AB switchbox› to the modem so it could serve the PC› as  well  as  the Atari.  Once again,› there really wasn't much to configure› for  each  machine,  and   a   simple› initialization  string  sent out from› each computer's terminal  program  at› bootup did the trick.›› My  next  PC contained an internal US› Robotics (now 3Com) 28.8  Kbps  modem› that was configured by the people who› assembled the PC for me.  Of  course,› I  went over the way it was done, and› read its manual  to  see  if  I could› duplicate    their    efforts,     if› necessary.   It became necessary when› I   switched   from  Windows  3.1  to› Windows   95.    The  modem  was  not› considered "plug-and-play," and I had› to  reconfigure everything again.  No› sweat!  Only a few hours of  my  time› to  make  the  switch  of   operating› systems,  with perhaps a half-hour or› less of that time taken up with modem› concerns.   Meantime,  my  Atari  was› still  happily  purring along at 2400› baud.  No Atari  file  that  I  could› find  was  so  large  that I couldn't› reasonably up- or download  it  in  a› short  time even at that slow speed. › PC files were another matter.  But  I› couldn't  help  thinking   what   the› process  would  be like if I switched› my Atari over to an external  version› of the modem I had in the PC.›› I've  had  many  opportunities  since› then  to  configure modems for fellow› Atari 8-bitters.   It  has  become  a› most frustrating experience for them,› and sometimes for me.  One source  of› that  frustration  is that modems are› sold with  the  assumption  that  you› will use them with a PC or Mac.  That› kind of  thinking  is  so  entrenched› that  the  modems  themselves have no› DIP   switches,  must  be  configured› through  software,  and  manuals  are› often not worth the  paper  on  which› they  are printed.  The manuals today› leave almost everything to the  setup› programs  included  on 3.5" floppy or› CD-ROM to be run on that  PC  or  Mac› the  modem  manufacturer  assumes you› will be using.  You're lucky  if  you› get  a  list  of  commands,  and then› there are often limited or  confusing› explanations of those commands.  But,› having been through the process  with› some  of the members, I felt prepared› to do it for Ron Fetzer when he asked› me to help him.›› Ron  was given a 56Kbps, external, US› Robotics modem by a  neighbor.    Ron› assumed, correctly, that he could run› the modem at up to  9600  baud  using› his  Atari  and  either  his  p:   R:› Connection  or his 850 Interface.  He› was not prepared for  the  fact  that› his  neighbor  had, somehow, lost the› manual and the power supply.  So, Ron› took  my  advice,  secured  a   power› supply  and   a   manual   from   the› manufacturer  and  tried the modem at› its   initial  factory  settings.  He› connected the modem  using  the  same› special Atari modem cable he had used› successfully   with   his  2400  baud› modem.  He fired up Ice-T  2.72,  set› the  baud  rate to 9600, and dialed a› number.    The   modem   dialed   and› connected,  but  then  would  neither› transmit nor receive data.›› Ron  brought  the  modem to the OHAUG› meeting in August, where we confirmed› what  it  was  doing.  However, under› the pressure of several people trying› to  fix  a 1050 disk drive at one end› of   the  room  and  the  anticipated› arrival  of  our  president  and  the› formal   start   of  the  meeting,  I› decided the modem had  to  come  home› with  me.   At home, I also confirmed› what the modem was doing.›› The  US  Robotics  manual  for  Ron's› modem is a bit better than most.   It› lists the commands, with descriptions› of each, in alphabetical  order.   It› also has, predictably, a lot of space› devoted to setting the modem up under› DOS,  under  Windows  3.1,  and under› Windows 95.   In  addition,  each  of› these  topics  is doubled because the› manual covers both the  internal  and› external  versions  of  this modem. I› didn't need any  of  that  stuff  for› this  job.   I did need the annotated› list of commands, and prayed  that  I› wouldn't    have    to    resort   to› configuring individual  s-registers. › I  was comforted by the fact that any› changes I made could be saved in what› is  refered  to  as "profiles" in the› modem's non-volatile memory.   So,  I› took  that  list  of   commands   and› divided  it  into  those  that had an› obvious impact  on  Ron's  situation,› those  that  obviously  didn't,   and› those  in  a gray area in-between.  I› decided that I'd try the first  group› right  away,  changing  each setting,› trying the modem,  and  changing  the› setting back if it didn't provide the› desired result.  At the end of  going› through this group, Ron's problem was› still not solved.›› I decided  to  try  the  questionable› commands next, and here's where I hit› pay-dirt.    The   command,   "AT&Rn"› turned  out  to  be  exactly  what  I› needed.   "AT&R0"   was   listed   as› RESERVED.   I  knew  that   was   not› appropriate.  "AT&R2" was the factory› default,  and  its  description  was,› "Received Data to  Computer  Only  on› RTS."   But,  "AT&R1 -- Modem Ignores› RTS,"  turned  out  to  be  correct. › After finding that out, I stored  the› setting  in   the   modem   with   an› "AT&W0."›› Now,  why  did  that  happen?   I had› previously, as part of my first group› of  commands,  put  the  modem   into› software flow control only, and there› was no change.  Also, the RTS line is› included  in  the Atari modem cable. › (I  know  --  I  checked  the  P:  R:› Connection manual for the pinout.)  A› call  to Frank Walters cleared up the› mystery.  Even though that line is in› the  cable,  and  PCs usually use it,› the Atari ignores the  state  of  the› RTS  line and, therefore, SO MUST THE› MODEM.  Ron now has a modem that will› function at 9600 baud -- faster if he› goes to a Black Box  or  MIO  --  and› I've learned something.›› I  think  a  note  here  about  modem› cables is appropriate, too.  If we 8-› bitters are going to use  non-direct-› connect modems, they must be external› modems, and they must be connected to› our  interface  with  a  cable.  This› cable may LOOK like a  "standard"  9-› pin  to  25-pin  RS-232 cable, but it› just isn't.   You  can't  go  into  a› computer  store  and  pick  up such a› "standard" cable  and  expect  it  to› work.   If  you  did, the first thing› you'd notice is that  the  9-pin  end› has  a  female  plug and so does your› interface!  You might be  tempted  to› go  back and pick up a gender-changer› to solve that problem.  The clerk  in› the  store  would be glad to sell you› one.  After  all,  he  sold  you  the› cable,  and  here's  one more item he› moved.  But when you  got  home,  the› cable  still wouldn't work.  You see,› the  "standard"  for  that  so-called› "standard" cable was developed by IBM› _AFTER_  Atari  had  produced the 850› Interface!  (Maybe we should claim to› be  standard  since  we  were   there› first,  but  that's another matter.) › So, what should you do?  One approach› is  to  take  a "standard" cable, cut› off the  9-pin  connector,  which  is› probably  factory-molded.  Then, with› the following pinout,  either  solder› or  crimp  the  leads  (which  you've› buzzed  out to identify them)  to the› pins of a DB9 male plug:››      DB25 Male      DB9 Male›      ---------      --------››       20              1›        8              2›        2              3›        3              4›        7              5›        6              6›        4              7›        5              8›      Frame to        No connection›      shield wire     to shield››› I've done this a  few  times,  but  I› don't  advise that you do it.  You'll› need the male plug, either crimp-  or› solder-type,  and  a  shell.  Add the› cost  of  those  items,  and  perhaps› tools and solder to  the  cost  of  a› factory-assembled  "standard"   cable› WHICH YOU MUST CUT, the time it takes› to trace out the leads (all 25 plus a› shield)  and  do  the   crimping   or› soldering,  and  you're  better   off› ordering  an  Atari  modem cable from› Best, B&C, or  American  TechniVision› (if  they  still  have  them.)    Any› factory-molded  cable  is going to be› more reliable than one that  you  can› assemble, anyway.››               o=o=o=o=o=›››