modem(7)						 Miscellaneous Information Manual						  modem(7)

NAME

       modem - Describes guidelines for using modems

DESCRIPTION

       The  Tru64  UNIX system enables you to use a variety of modems for point-to-point connections to systems that are not in close proximity to
       each other.  These connections can be Serial Line Internet Protocol (SLIP), Point-to-Point Protocol (PPP), and  UNIX-to-UNIX  Copy  Program
       (UUCP)  connections. In addition, these connections can be basic dial-out/dial-in connections (for example, to log in to a remote system to
       perform remote system administration).

       This section presents general guidelines for using modems on Tru64 UNIX systems for all types of connections.  See  Network  Administration
       for specific information on SLIP, PPP, and UUCP connections.

   Using the Correct Modem Cables
       In  order  to connect a modem to the serial port of your system, you must use the correct cable. If you do not, you might experience signal
       loss, resulting in the software not functioning properly. The following table lists the cables you should  use.	 The  cable  connector	is
       either  25-pin  or  9-pin,  depending  on the type of serial port on your system. See the hardware documentation for your system if you are
       unsure about the type of serial port.

									  Note
       OPEN DECconnect cables do not provide a sufficient number of wires for full modem control.  You should not use them for	connecting  modems
       to the system.

       ------------------------------------------------------------------------------
       Cable Number	Description
       ------------------------------------------------------------------------------
       BC22E-xx 	16-wire modem cable (Male DB25 pin to female DB25 pin cable)

       BC22F-xx 	25-wire modem cable (Male DB25 pin to female DB25 pin cable)

       BC29P-xx 	Male DB25 pin to female DB9 pin cable

       PC modem cable	Male DB25 pin to female DB9 pin cable

       In the previous table, xx denotes the cable length. For example, BC22E-10 is a ten-foot cable.

   Configuring a System for Dial-In Access
       After  you have obtained the correct cable and connected your modem to it and the telephone network, do the following: Edit the /etc/remote
       file and create an entry similar to the kdebug entry. For example, if your modem is connected to tty00 and you are going to use a baud rate
       of 38400 to access the modem, create an entry similar to the following: b38400:dv=/dev/tty00:br#38400:pa=none

									      Note
	      Some modems set their baud rate to the serial port rate.	Be sure to access the modem using the same baud rate that you are going to
	      specify to getty or uugetty. Otherwise, you might not be able to log in because of a mismatch in baud rates.

	      See ports(7) if you are unsure which port your modem is connected to.  Use the tip command to  access  the  modem  as  follows:  tip
	      b38400

	      The  tip	utility  responds with a connected message. You can now communicate with the modem.  If your modem is using the AT command
	      language, enter the following command: at<Return>

	      If the modem is not in quiet mode, it responds with an OK message.  Set the modem up for dial-in access.	The following table  lists
	      the AT commands required.  Most of these command settings are the default settings.

	      --------------------------------------------------------------------------
	      Command	Description
	      --------------------------------------------------------------------------
	      at&c1	Normal Carrier Detect (CD) operation.  Tells the modem to not
			raise Carrier Detect until it see Carrier Detect from the other
			modem.

	      at&d2	Normal Data Terminal Ready (DTR) operation.  This is
			important in that it tells the modem to hang up the line when
			DTR drops.  For example, when the user logs off the system.

	      atq1	Sets the modem into quiet mode. Result codes are not sent to
			the system.

	      ate0	Echo off. This prevents the modem from echoing back the login
			prompt issued by the getty process.

	      ats0=n	Specifies the number of rings to wait before answering.  If
			n = 0 (zero), the modem will not answer.

	      at&w0	Saves the current modem settings in NVRAM.

	      The operating system  supports both hardware and software flow control.  If the system supports hardware flow control, set the modem
	      and the serial line up to use hardware flow control by using the appropriate commands.  If hardware flow control is  not	supported,
	      you  should  use	software flow control.	Edit the /etc/inittab file and create an entry for the modem. If you want to use the modem
	      line in non-shared mode, create an entry similar to the following: modem:23:respawn:/usr/sbin/getty /dev/tty00 M38400 vt100

	      If you want to use the modem line in shared mode (for dial-out and dial-in connections), use uugetty instead of getty and create	an
	      entry similar to the following: modem:23:respawn:/usr/lib/uucp/uugetty -r -t 60 tty00 38400

	      With  uugetty,  you will be able to use the tip and cu utilities, but might not be able to use third-party utilities because of dif-
	      ferences in file locking.

									      Note
	      If you want to use the uugetty utility, you must install the UNIX-to-UNIX Copy Facility subset.
	      As root, start the getty or uugetty process by entering the following command: init q

	      The getty or uugetty process starts, then goes to sleep, waiting for someone to dial into the system.

   Configuring Your System for Dial-Out Access
       After you have obtained the correct cable and connected your modem to it and the telephone network, do the following: Verify that there	is
       an  entry  for the modem name specified with the modemtype subcommand in the /etc/acucap file.  If your modem does not have an entry in the
       /etc/acucap file, do the following: Copy an entry similar to that of your modem.  The following entry is for a US Robotics modem for use in
       shared mode with tip: us|US|US Robotics (28.8 fax/data modem):
	     :cr:hu:ls:re:ss=AT
ATE1Q0&C0X0&A0
:sr=OK:
	     :sd#250000:di=ATD:dt=
:
	     :dd#50000:fd#50:os=CONNECT:ds=d+++dATZ
dATS0=2
:
	     :ab=d+++dATZ
dATS0=2:

	      Be sure the entry includes at least the AT commands in the following table.  The other modem settings can remain as they are.

	      -------------------------------------
	      Command	Description
	      -------------------------------------
	      ate1	Turns on echoing.

	      atq0	Displays the result codes.

	      Modify  the modem attributes to match your modem's attributes and include the debug option (db). With debugging turned on, the modem
	      will provide you with additional information with which to tune the modem attributes in the file. See acucap(4)  for  more  informa-
	      tion.   Create  an entry in the /etc/remote for the system you want to call.  Among the information you can supply is the Tru64 UNIX
	      device, baud rate, and /etc/acucap that defines your modem.  The following two entries are for  the  modem  specified  in  step  1a.
	      tip38400:tc=us38400 us38400|38400 Baud dial out via US Robotics modem:
		    :el=^U^C^R^O^D^S^Q@:ie=#%$:oe=^D:
		    :dv=/dev/tty00:br#38400:ps=none:at=us:du:

	      In the previous example, the first line is an entry that points to the us38400 entry specifying shared capabilities for modems.  The
	      second line is the first line of the us38400 entry. The third line defines end-of-line characters, and input and output  end-of-file
	      marks.   The  fourth line defines the UNIX device to open for the connection, the baud rate, the parity, the name of the /etc/acucap
	      file entry, and the dial-up line.

	      See remote(4) for more information.  If you use getty to provide access to the system from a modem and a getty  process  is  already
	      running,	do  the  following: Edit the /etc/inittab file and put a comment character (#) at the beginning of the modem entry.  Issue
	      the init q command to terminate the getty process.  Use the tip command, specifying the -baud_rate flag and the telephone number	to
	      dial out as follows: tip -38400 8881234

	      In  this	example,  tip  strips off the minus sign (-) from the baud rate and concatenates the tip command name and the baud rate to
	      create the string tip38400.  Then, tip searches the  /etc/remote	file  for  the	entry  matching  the  string.  The  entry  in  the
	      /etc/remotes file, points the capability information in the us38400 entry to initialize the modem.

	      By  specifying  the telephone number on the command line, you can share the same modem attributes for outgoing connections that have
	      different telephone numbers.

	      When you log off the remote system and exit tip, the modems saved settings are restored, readying the modem for the next	user.	If
	      used in shared mode, the modem is available for dial-in access.

RELATED INFORMATION

       Commands: cu(1), tip(1), getty(8), uugetty(8).

       Files: acucap(4), inittab(4), remote(4).

       Devices: ports(7).

       Network Administration delim off

																	  modem(7)