peripheral device know when the computer is ready to accept  another  character  and  vice  versa.  This  type  of transmission is used when you want to have fast data transfer. Its drawback is that the computer cannot be too far away from the peripheral device. MODEMS We  said  that  both  signals  and  data  can  be transmitted and received through cables (communica- tions lines), which we refer to as I/O charnels. When we  transmit  data  directly  to  the  computer  over  long distances,   it   becomes   necessary   to   add   two   other devices, one at each end of the communications line. These devices are called  modems. The word modem is an  acronym  for  MOdulator-DEModulator.  A  modem converts the digital signal produced by your terminal (or   the   computer)   to   an   audio   signal   suitable   for transmission   over   the   communications   line.   The modem at the other end of the line reconverts the audio signal back to a digital signal before it is supplied to the computer (or your terminal). If this conversion were not carried  out,  the  digital  signal  would  degenerate  and become garbled during transmission. WORKING  WITH  MICROCOMPUTERS Microcomputers   are   everywhere.   They   stand alone. They communicate with minis and mainframes. They  communicate  with  other  micros  through  local- area  networks.  This  communication  is  accomplished by the use of software designed to make your computer system   function. The  operating  system  software enables you to install, select, and execute a variety of programs.   It   does   this   through   system/job   control languages and/or commands. Microcomputer   users   are   not   often   computer specialists. They are end users in the functional areas doing   computer   processing   specific   to   their requirements. They need to know about the software: the  operating  system,  the  communication  software,  and the  applications  programs.  They  need  to  know  about the  hardware:  the  microcomputer,  the  hard  disks  and the  floppies,  the  monitor,  the  keyboard,  and  the  printer. You  will  need  to  help  them  configure  (set  up)  the system,  install  the  operating  system  and/or  applications program, and troubleshoot problems. You need to know more than just merely how to operate them if you are to become a communications specialist. To be effective, you must keep up with the latest   changes   in   microcomputer   technology   and terminology. You   must   have   a   good   working knowledge  of  microcomputer  hardware  components 1-10 (the   computer,   peripherals,   and   accessories).   You should also be able to explain and demonstrate how to use  the  different  types  of  systems  and  applications software  to  both  computer  and  noncomputer  personnel. Last,  but  not  least,  you  should  know  how  to  use  the various   types   of   documentation   supplied   by   the manufacturer and software vendors. As a communications specialist, you must be able to   set   up,   configure,   upgrade,   and   initialize microcomputer  systems.  You  will  need  to  know  how  to install   applications   software   so   it   works   with   the system’s  unique  configuration.  It  will  be  your  job  to help   noncomputer   users,   end   users,   learn   and understand everything they need to know to work in a microcomputer   environment.   This   includes   how   to interconnect   various   peripheral   devices   (keyboard, monitor,  printer)  to  the  computer  or  system  unit.  It  also includes  how  to  tailor  the  software  for  the  operating system  and  the  applications  software  to  each  user’s unique  hardware  configuration.  You  need  to  teach  them how  to  format  and  label  diskettes;  how  to  properly manage, back up, clean up, and store their files. You need to demonstrate routine operator maintenance and explain  security  procedures.  When  users  are  having problems with their micros, you may be called upon to troubleshoot  the  systems  using  system  diagnostics  to help  isolate  and  determine  whether  the  problem  is hardware or software related. You will also be expected to  make  recommendations  and/or  arrangements  to  have repairs  made.  There  will  be  times  when  you  will  be expected to make repairs if spare parts are available. On  microcomputers,  you  will  need  to  be  familiar with  all  types  of  productivity  software—the  program packages (or packaged software). These include word processing,  spreadsheet,  and  database  programs  at  a minimum.  You  also  need  to  learn  how  to  use  local-area network software, communications programs, graphics programs,   computer-aided   design   (CAD)   programs, desktop  publishing  programs,  and  so  on.  You,  as  a professional data processor, may also be involved with the construction and modification of batch files. This provides a convenient way to save numerous keystrokes for the user and allow the computer to run unattended for   some   periods   of   time.   All   of   these   software functions can and have been implemented on both large and small scale computers. On large computer systems, you maybe executing programs   through   system/job   control   language commands  and  processing  jobs  with  multi-reel  tape files  or  files  that  reside  on  disk  packs.  You  will  be responsible  for  ensuring  that  system  control  commands