Return to modem CVS log

Up to [MW Coherent from dump] / coherent / a / usr / man / COHERENT

Annotation of coherent/a/usr/man/COHERENT/modem, revision 1.1

1.1     ! root        1: 
        !             2: 
        !             3: modem                 Technical Information                 modem
        !             4: 
        !             5: 
        !             6: 
        !             7: 
        !             8: The word  _m_o_d_e_m is an  abbreviation for ``modulation/demodulation
        !             9: device''.  With  the COHERENT system,  you can attach  a modem to
        !            10: your computer either to dial out for remote communication, to let
        !            11: others dial into your COHERENT system, or both.  With your modem,
        !            12: too, you  can use COHERENT's  UUCP commands to  exchange mail and
        !            13: files with  remote sites automatically, and  to download news and
        !            14: files from the USENET.
        !            15: 
        !            16: This article gives a summary of how to connect your modem to your
        !            17: computer  and  describe  it  to  the  COHERENT system.   It  also
        !            18: discusses some problems that may  crop up when you attempt to use
        !            19: your modem.
        !            20: 
        !            21: ***** Internal vs. External Modems *****
        !            22: 
        !            23: You  can use  internal  and external  modems  with COHERENT.   An
        !            24: internal modem  is, however, more difficult  to diagnose problems
        !            25: because  there  are   typically  no  status  lights  to  indicate
        !            26: operation.
        !            27: 
        !            28: ***** Hooking up a Modem *****
        !            29: 
        !            30: A modem must be hooked up  to a serial port on your computer.  To
        !            31: plug your  modem into the computer, simply  take a normal serial-
        !            32: port cable, one with an  RS-232 plug of the appropriate gender at
        !            33: each end,  plug one end  into your modem  and the other  into the
        !            34: serial  port  you  wish  to  use.   The  Lexicon  article  RRSS-223322
        !            35: describes the wiring of the RS-232 plug in detail; but if you are
        !            36: not skilled with a soldering iron, you are well advised simply to
        !            37: purchase a  cable from your  local electronics store  and be done
        !            38: with it.
        !            39: 
        !            40: ***** Serial Ports *****
        !            41: 
        !            42: The COHERENT system supports up to four serial ports; the devices
        !            43: for these are named /ddeevv/ccoomm11rr through /ddeevv/ccoomm44rr. If you are not
        !            44: sure which  port you  have plugged  your modem into,  perform the
        !            45: following  test:  First,  turn  on  the  modem.  Then,  type  the
        !            46: following command:
        !            47: 
        !            48: 
        !            49:         echo FOO >/dev/com1l
        !            50: 
        !            51: 
        !            52: If the ``TX'' light on the  modem blinks, then you know the modem
        !            53: is plugged into  CCOOMM11. If it does not, try  the command again for
        !            54: /ddeevv/ccoomm22ll,  and   so  on  through  ccoomm44ll   until  you  find  the
        !            55: appropriate port.  If no  command works, check the wiring on your
        !            56: cable and make sure that the plugs are securely inserted.
        !            57: 
        !            58: Once you have established  which port your modem is plugged into,
        !            59: links the device /ddeevv/mmooddeemm to it, using the following command:
        !            60: 
        !            61: 
        !            62: 
        !            63: 
        !            64: COHERENT Lexicon                                           Page 1
        !            65: 
        !            66: 
        !            67: 
        !            68: 
        !            69: modem                 Technical Information                 modem
        !            70: 
        !            71: 
        !            72: 
        !            73: 
        !            74:         ln -f /dev/com?l /dev/modem
        !            75: 
        !            76: 
        !            77: where ? gives the number of the port, 1 through 4.
        !            78: 
        !            79: ***** Edit /etc/ttys *****
        !            80: 
        !            81: The next step is to edit  the file /eettcc/ttttyyss to tell COHERENT how
        !            82: you want  the port handled.   You must know (1)  whether you want
        !            83: the port enabled  or disabled; (2) the baud rate  of the port (as
        !            84: set by your modem); and (3)  the name of the port (which you just
        !            85: determined).
        !            86: 
        !            87: If  a port  is enabled,  remote  users can  log into  the system,
        !            88: either via  a terminal  directly plugged into  the port or  via a
        !            89: modem.  COHERENT sends a login prompt to every enabled port.  The
        !            90: COHERENT system also  restricts permissions on all enabled serial
        !            91: ports, so that only the superuser  rroooott can read and write to the
        !            92: port.  This prevents other users who may be using the system from
        !            93: accessing the  serial port.  If a port is  disabled, you can dial
        !            94: out  or use  a direct-connect UUCP  connection via  that disabled
        !            95: port.
        !            96: 
        !            97: To dial  out on an enabled  port, you must first  use the command
        !            98: ddiissaabbllee to disable the port.  When you have finished dialing out,
        !            99: run the command eennaabbllee to re-enable the port.  Before you can use
        !           100: these commands  with a port, the port must  first be described in
        !           101: the file /eettcc/ttttyyss.
        !           102: 
        !           103: See the Lexicon  article on ttttyyss for details on  how to edit this
        !           104: file.   Note that  a modem  is a  remote device,  and must  be so
        !           105: described in /eettcc/ttttyyss, or it will not work correctly.
        !           106: 
        !           107: After you have made your changes, type the command
        !           108: 
        !           109: 
        !           110:         kill quit 1
        !           111: 
        !           112: 
        !           113: to make COHERENT re-read /eettcc/ttttyyss and implement your changes.
        !           114: 
        !           115: ***** Remote-Access Password *****
        !           116: 
        !           117: If you intend to let people dial into your computer, you are well
        !           118: advised  to set  the remote-access  password.  This  will require
        !           119: that people  who dial in  know a special password  in addition to
        !           120: whatever password  their personal account may  have.  To set this
        !           121: password, log in as the superuser rroooott; then enter the command
        !           122: 
        !           123: 
        !           124: 
        !           125: 
        !           126: 
        !           127: 
        !           128: 
        !           129: 
        !           130: COHERENT Lexicon                                           Page 2
        !           131: 
        !           132: 
        !           133: 
        !           134: 
        !           135: modem                 Technical Information                 modem
        !           136: 
        !           137: 
        !           138: 
        !           139:         passwd remacc
        !           140: 
        !           141: 
        !           142: This will  walk you through  setting a password  for user rreemmaacccc,
        !           143: which is the remote-access account.
        !           144: 
        !           145: ***** Edit /etc/modemcap *****
        !           146: 
        !           147: Next, you must check the  file /eettcc/mmooddeemmccaapp and see if that file
        !           148: holds a description that matches your modem.  mmooddeemmccaapp is used by
        !           149: a number  of programs to control access to  modems, and this file
        !           150: comes with descriptions for many commonly used modems.  You find,
        !           151: however,  that you  must  edit an  existing entry  to match  your
        !           152: modem's  features exactly;  for example,  the existing  entry may
        !           153: assume that you  have a Touch-Tone telephone whereas you actually
        !           154: have a pulse telephone.   The Lexicon entry on mmooddeemmccaapp will walk
        !           155: you through  this process.  When you  have completed editing this
        !           156: entry, note it down, for you will need to insert it elsewhere.
        !           157: 
        !           158: ***** Edit /usr/bin/modeminit *****
        !           159: 
        !           160: Next, check the  file /uussrr/bbiinn/mmooddeemmiinniitt. This program is read by
        !           161: programs  that manipulate  the modem,  to re-initialize  it after
        !           162: use.   You  must  decide  how  you  want  the  modem  to  be  re-
        !           163: initialized.   Basically, if  you wish to  have people  dial into
        !           164: your system, you turn on the modem's auto-answer feature; and you
        !           165: must  turn off  echoing and  the printing  of result  codes.  The
        !           166: commands  to  use  will   vary  from  modem  to  modem;  see  the
        !           167: documentation that comes  with your modem for details.  See below
        !           168: for details on modifying this script.
        !           169: 
        !           170: ***** Edit L-devices *****
        !           171: 
        !           172: If you  intend to use  your modem with  UUCP, you must  insert an
        !           173: entry for it  into your the file /uussrr/lliibb/uuuuccpp/LL-ddeevviicceess. See the
        !           174: Lexicon entry LL-ddeevviicceess for details.
        !           175: 
        !           176: ***** Modem Maladies *****
        !           177: 
        !           178: The rest of this article discusses problems that have arisen with
        !           179: remote  login via  modem, as diagnosed  by the  technical support
        !           180: staff of Mark Williams Company.
        !           181: 
        !           182: Difficulty in logging in from a  remote site via modem can be the
        !           183: result  of problems  in one  or more  of the  following: cabling;
        !           184: enabling/disabling  the  port;  flaws  in  the contents  of  file
        !           185: /eettcc/ttttyyss; incorrect configuration  of the modem; and setting the
        !           186: port to  an incorrect state.   See Lexicon articles  tteerrmmiinnaall and
        !           187: UUUUCCPP  for  additional   information.   The  following  paragraphs
        !           188: discuss the above-named items in detail.
        !           189: 
        !           190: ***** RS-232 Cabling *****
        !           191: 
        !           192: When  attaching  an  external  modem  to  your  computer,  it  is
        !           193: important  to  use  a  modem  cable  that supports  ``full  modem
        !           194: 
        !           195: 
        !           196: COHERENT Lexicon                                           Page 3
        !           197: 
        !           198: 
        !           199: 
        !           200: 
        !           201: modem                 Technical Information                 modem
        !           202: 
        !           203: 
        !           204: 
        !           205: control''.   COHERENT   relies  on  modem-control   signals  when
        !           206: operating a  modem for remote access  purposes.  When attaching a
        !           207: terminal directly  to a serial port, a  ``null modem'' cable must
        !           208: be used.   When attaching a  modem, a ``straight  through'' cable
        !           209: must  be used.   See  Lexicon articles  RRSS-223322  and tteerrmmiinnaall  for
        !           210: further details on cabling.
        !           211: 
        !           212: ***** Enabled vs. Disabled Ports *****
        !           213: 
        !           214: A  serial  port can  be  either enabled  or  disabled for  remote
        !           215: access.  Enabling  a port allows  a user on a  remote terminal or
        !           216: modem to log into your COHERENT system.  Disabling a port permits
        !           217: a user  to dial out or  use a direct connect  UUCP connection via
        !           218: that disabled port.
        !           219: 
        !           220: If a  port is enabled  for remote logins  and you will  use it to
        !           221: call out,  you must use  the command ddiissaabbllee to  disable the port
        !           222: before  you  access   the  port.   The  commands  uuuuccpp  and  mmaaiill
        !           223: automatically disable and re-enable a port.
        !           224: 
        !           225: The  port name  supplied  to an  eennaabbllee or  ddiissaabbllee command  must
        !           226: _e_x_a_c_t_l_y match the last part of  a line in the /eettcc/ttttyyss file (see
        !           227: below).   For example,  for the  command  eennaabbllee ccoomm22pprr  to work,
        !           228: there  must be  an entry  in the file  /eettcc/ttttyyss which  ends with
        !           229: ccoomm22pprr.
        !           230: 
        !           231: When a port  is enabled, (1) the first character  for the port in
        !           232: file /eettcc/ttttyyss is set to a `1' (one), (2) the permissions for the
        !           233: port are  changed so  that only the  superuser rroooott can  read and
        !           234: write  to the  port, preventing  other users  on the  system from
        !           235: accessing the port while a remote session is in progress, and (c)
        !           236: a login prompt is sent to the port.
        !           237: 
        !           238: ***** /etc/ttys *****
        !           239: 
        !           240: This file should  have permissions of 644 (-rw-r--r--) and belong
        !           241: to owner  and group  rroooott. Review the  Lexicon entry for  ttttyyss to
        !           242: ensure that the format of your version of /eettcc/ttttyyss is correct.
        !           243: 
        !           244: Leaving blanks at the end  of a line in /eettcc/ttttyyss usually results
        !           245: in error messages stating that a device could not be found.
        !           246: 
        !           247: You do  not need  to edit  the initial `0'  or `1' in  entries in
        !           248: /eettcc/ttttyyss;  this digit  is  updated by  the  commands eennaabbllee  and
        !           249: ddiissaabbllee. See the Lexicon  entries for eennaabbllee and ddiissaabbllee for more
        !           250: information.
        !           251: 
        !           252: Another problem  can arise when using  a variable-speed modem and
        !           253: specifying  the  baud rate  as  `3' in  file  /eettcc/ttttyyss. The  `3'
        !           254: setting represents a 2400-1200-300 baud variable-speed port.  The
        !           255: problem appears  to be that while a modem  defaults to 2400 baud,
        !           256: COHERENT may  actually be  set at one  of the other  speeds.  The
        !           257: answer to this probem is to run the command mmooddeemmiinniitt.
        !           258: 
        !           259: 
        !           260: 
        !           261: 
        !           262: COHERENT Lexicon                                           Page 4
        !           263: 
        !           264: 
        !           265: 
        !           266: 
        !           267: modem                 Technical Information                 modem
        !           268: 
        !           269: 
        !           270: 
        !           271: ***** Constant Flickering *****
        !           272: 
        !           273: Another problem is a constant flickering of send/receive LEDs and
        !           274: an unexplained  continual access of the  hard drive.  This occurs
        !           275: when  the port  is enabled  and the  modem is  set in  echo mode:
        !           276: COHERENT sends the login prompt to the modem, the modem echoes it
        !           277: back to  COHERENT, COHERENT  then thinks  the modem is  trying to
        !           278: talk to it and sends the password prompt, and so on _a_d _i_n_f_i_n_i_t_u_m.
        !           279: To fix this problem, place  the modem into no-echo mode, and turn
        !           280: off the display of result codes.  The following section discusses
        !           281: this in more detail.
        !           282: 
        !           283: ***** Modem Configuration *****
        !           284: 
        !           285: A modem  that fails to  answer an incoming call,  hangs up before
        !           286: locking onto the remote  carrier, becomes stuck in a loop echoing
        !           287: characters sent  to it from the computer, or  fails to operate at
        !           288: the  expected baud  rate probably  is configured  improperly.  To
        !           289: remedy this situation, send the appropriate control string to the
        !           290: modem.
        !           291: 
        !           292: We  offer some  guidelines here for  modem settings.   Be warned,
        !           293: however, that modems  from different manufacturers usually behave
        !           294: differently,  regardless of  claims of  Hayes  compatibility, and
        !           295: that you will need to check the manual for your particular modem.
        !           296: 
        !           297: -> Echo should be OFF (usually by setting ``E0'').
        !           298: 
        !           299: -> Result codes should be OFF (usually by setting ``Q1'').
        !           300: 
        !           301: -> Modem status ``DCD'' should follow true carrier detect status,
        !           302:    rather than being always on (usually by setting ``&C1'').
        !           303: 
        !           304: -> Auto answer should be ON (usually obtained by setting register
        !           305:    S0  to a  nonzero value  equal to the  number of  rings before
        !           306:    answer).
        !           307: 
        !           308: -> The delay  value for  ``Wait for Carrier/Dial  Tone'' (usually
        !           309:    register S7) should not be too short.
        !           310: 
        !           311: The  scripts  below  show  typical  initialization  for  ``Hayes-
        !           312: compatible''  and Trailblazer  modems.  They  are  only examples;
        !           313: your modem  may need something  different.  Please note  that the
        !           314: commands sslleeeepp  and ssttttyy  are necessary  in the first  example so
        !           315: that the command  string will be sent to the  modem at 2400 baud;
        !           316: otherwise, the string is sent at the default port speed, which is
        !           317: 9600 baud.
        !           318: 
        !           319: 
        !           320:         # initialize 2400-baud Hayes-compatible modem
        !           321:         disable com3r
        !           322:         sleep 3 > /dev/com3l &
        !           323:         stty 2400 > /dev/com3l
        !           324:         echo 'AT E0 Q1 V0 S0=1 &C1 M3' > /dev/com3l
        !           325:         sleep 3
        !           326: 
        !           327: 
        !           328: COHERENT Lexicon                                           Page 5
        !           329: 
        !           330: 
        !           331: 
        !           332: 
        !           333: modem                 Technical Information                 modem
        !           334: 
        !           335: 
        !           336: 
        !           337:         enable com3r
        !           338: 
        !           339: 
        !           340: 
        !           341:         # initialize 9600 baud internal Trailblazer on com2
        !           342:         /etc/disable com2r
        !           343:         cat > /dev/com2l << EOF
        !           344:         at
        !           345:         at e0 t v0 x3 h0
        !           346:         at s0=1 s7=60 s48=1 s51=252 s52=0 s54=3 s58=2
        !           347:         at
        !           348:         EOF
        !           349:         /etc/enable com2r
        !           350: 
        !           351: 
        !           352: You can edit the  file /uussrr/bbiinn/mmooddeemmiinniitt to suit your modem.  To
        !           353: ensure  that  your  modem is  initialized  every  time you  start
        !           354: COHERENT, you should add a line saying
        !           355: 
        !           356: 
        !           357:         /usr/bin/modeminit
        !           358: 
        !           359: 
        !           360: to your copy of the file /eettcc/rrcc.
        !           361: 
        !           362: ***** See Also *****
        !           363: 
        !           364: mmooddeemmccaapp, RRSS-223322, tteecchhnniiccaall iinnffoorrmmaattiioonn, tteerrmmiinnaall
        !           365: 
        !           366: ***** Notes *****
        !           367: 
        !           368: One  final  bit  of  hard-won  wisdom:  once you  have  something
        !           369: working, write down  what you did, and store it  in a place where
        !           370: you won't lose it.  It makes life easier just knowing that you're
        !           371: looking for a female-to-female cable instead of male-to-female or
        !           372: male-to-male.
        !           373: 
        !           374: 
        !           375: 
        !           376: 
        !           377: 
        !           378: 
        !           379: 
        !           380: 
        !           381: 
        !           382: 
        !           383: 
        !           384: 
        !           385: 
        !           386: 
        !           387: 
        !           388: 
        !           389: 
        !           390: 
        !           391: 
        !           392: 
        !           393: 
        !           394: COHERENT Lexicon                                           Page 6
        !           395: 
        !           396: 

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.