Using External Modems   10

  This chapter explains how to configure external modems to work with the PortMaster 4. The information in this chapter does not apply to the internal digital modems that come installed on Quad T1 and Tri E1 boards with modems.

  Note ¯ ComOS 4.0 and ComOS 4.1 do not support the add modem , delete modem , and show modem  commands for external modems. If you are running ComOS 4.0 or ComOS 4.1 on the PortMaster 4, you cannot use the commands in this chapter to configure external modems on asynchronous ports C0 and C1. Instead, you can attach a previously configured modem to the C0 or C1 ports. Although you cannot display the modem's settings with the show modem  command, it will function if properly configured.

  This chapter discusses the following topics:

•  "Modem Ports" on page 10-1
•  "Modem Functions" on page 10-2
•  "Using Automatic Modem Configuration" on page 10-2
•  "Configuring Ports for Modem Use" on page 10-5

  See the PortMaster 4 Command Line Reference for more detailed command descriptions and instructions.

  Because the PortMaster is a DTE device, a straight-through RS-232 cable is used to connect modems to it. Straight-through cables for modems use pins 2, 3, 4, 5, 6, 7, 8, and 20. See the PortMaster 4 Installation Guide for modem cable information.

  You can also configure the PortMaster 4 using the PMVision application for Microsoft Windows, UNIX, and other platforms supporting the Java Virtual Machine (JVM). PMVision replaces the PMConsole interface to ComOS.

       Modem Ports

  The PortMaster 4 supports external modems on two asynchronous ports (C0 and C1), which are physically located on the manager module. Although you can attach a modem to port C0, it is primarily designed to be used for a console connection with a null modem cable. Port C1 is a standard asynchronous interface designed for connection to an external modem.

  To connect these ports to a terminal or other DTE, use a null modem cable, typically male-to-female. Directions (input/output) are with respect to the PortMaster. The PortMaster does not use the Data Set Ready (DSR) signal.

  Note ¯ When the console port is connected to a terminal, it uses software flow control and therefore requires pins 2, 3, and 7 only.

  Null modem cables can be obtained from most suppliers of computer equipment.

  Dial-up modems that operate over normal telephone lines at speeds of 28,800bps or higher are now available. These modems do not operate at a guaranteed throughput, but rather at a speed dependent on the quality of the line, the effectiveness of data compression, and other variables. These modems use hardware flow control to stop the data from the host by raising and lowering the Clear to Send (CTS) signal.

  PortMaster products support hardware flow control using the RTS output signal and the CTS input signal, which is also used by the normal modem handshake.

       Modem Functions

  Configure modems to do the following for use with the PortMaster:

•  Raise DCD when a call comes in
•  Reset itself when DTR is dropped
•  Lock the DTE speed
•  Use hardware flow control (RTS/CTS)

       Using Automatic Modem Configuration

  PortMaster products use a modem table to automate the external modem configuration process. The modem table is user-configurable and includes long and short modem names, preferred DTE rate, and the modem initialization string. For convenience, the table is preconfigured by Lucent for many common modems.

  When you specify the name of the modem and the attached port, the PortMaster automatically configures the modem for you, provided the modem is in the factory default state when it is initialized.

  After a modem type has been specified, the PortMaster automatically sets the port for hardware flow control, the correct speed, and modem control when the port is reset.

       Displaying Modem Settings and Status

  To display the external modems currently configured in your modem table, use the following command:

  Command> show table modem 

  A modem table display looks like the following:

Short Name	Long Name	Type
--------------	-------------	------
cardinal	Cardinal MVP288XF	System
mega	Massive MegaFast	User
supra-288	Supra V.34	System

  The modem type  is either system or user. System indicates that the configuration settings are the factory default settings. User indicates that the user has configured the modem table settings for that modem.

  To display the settings for a particular modem, use the following command:

  Command> show modem  ModemName(short)

  The display for a modem looks like this:

Short Name:	supra-fax-288
Long Name:	SupraFax 28.8
Optimal Speed:	115200
Type:	User Defined
Init Script:	Send Command	Wait for Reply
	-------------------------------------------	------------------
	AT&F2&C1&D3S0=1S2=129s10=20&W	OK

       Adding a Modem to the Modem Table

  To add a modem to the modem table, use the following command:

  Command> add modem  ModemName(short) "ModemName(long)" Speed "String"

  For example, to add a Paradyne 3811+ modem to the modem table, enter:

  Command> add modem para3811 "Paradyne 3811+" 115200 "AT&FS0=1&W\r^OK"  

  Note ¯ Use a \r  for a carriage return, and a caret (^ ) to separate the send and expect characters in the string. In the example above, the PortMaster expects OK . Never use on  or off  for a modem short name.

  Table 10-1 shows the current factory default settings for commonly used modems.

  Table 10-1 Factory Default Modem Table Entries 

 

Modem Name (Short)	Modem Name (Long)	DTE Rate	Initialization String
at&t-v32	AT&T Keep In Touch	57600	AT&F&D3&T5&R0\\D1S0=1&W^OK
cardinal	Cardinal MVP288XF	115200	AT&F1&C1&D2&K3S0=1S2=129S10=20&W0&W1
card-v34-p	Cardinal MVP288CC PCMCIA	115200	AT&F&C1&D3S0=1s2=129S10=20&W
eiger-v32-p	Eiger 14.4 PCMCIA	57600	AT&F&C1&D3S0=1S10=20&W
eiger-v34-p	Eiger 28.8 PCMCIA	115200	AT&F&C1&D3S0=1S10=20&W
gvc-14.4	GVC/Maxtech V.32	57600	AT&F&C1&D3S0=1S10=20&W0
gvc-28.8	GVC/Maxtech V.34	115200	AT&F&C1&D3S0=1S10=20&W0
hay-cent2	Hayes Century 2 Rack V.32bis	115200	AT&F&C1&D2&K3S0=1S10=20&W0
intel-v32-p	Intel V.32bis PCMCIA	115200	AT&F&C1&D3S0=1&W&W1^\rOK
megahz-v32-p	Megahertz XJ2288 V.34bis PCMCIA	115200	AT&F&C1&D3S0=1&W
megahz-v32-p	Megahertz XJ2288 V.34bis PCMCIA	115200	AT&F&C1&D3S0=1&W
micro-desk	Microcom 28.8	115200	AT&F&C1&D2$B115200\\Q3%U1&T5S0=1S10=20*W0&Y0
mot-uds	Motorola UDS V.34	115200	AT&F&C1&D2\\Q3S0=1S10=20S80=18&W
mot-bit	Motorola Bitsurfr	115200	AT&F&C1&D2%A4=1%A2=95&m0@P2=115200@P1=a&W
mot-pwr-p	Motorola Power 14.4 PCMCIA	57600	AT&F&C1&T5&C1&D2&W
mot-life-p	Motorola Lifestyle 14.4 PCMCIA	57600	AT&FS0=1&C1&D2\\Q3&T5&W^OK
multizdx	MultiTech Z/DX fax/data v.32	115200	AT&F^ATM0&E1&C1&D3$SB115200S0=1S10=20%E0&W0
multi-v34	MultiTech MT2834 28.8k	115200	AT&F^AT&C1&D3S0=1&W0
multi-v34	MultiTech MT2834 28.8k	115200	AT&F^AT&C1&D3S0=1&W0
pp-v32	Practical Peripherals PP9600SA	57600	AT&F&C1&D3S0=1S2=129&W
pp-v34	Practical Peripherals PM288T II	115200	AT&F0M0S0=1V1&C1&D3&K3&W0&W1
para3811	Paradyne 3811+	115200	AT&FS0=1&W
ppi-v34-p	PPI ProClass V.34 PCMCIA	115200	AT&F&C1&D3&K3S0=1&W&W1
premax-v32-p	Premax V.32bis PCMCIA	115200	AT&F&C1&D3S0=1&W&W1
scout-v32-p	DSI Scout V.32bis PCMCIA	115200	AT&F&C1&D3S0=1&W
supra-288	Supra V.34	115200	AT&F2S0=1&W
supra-fax-288	SupraFax 28.8	115200	AT&F2&C1&D3S0=1S2=129s10=20&W
tdk-288-p	TDK DF2814 V.Fast PCMCIA	115200	AT&F&C1&D3S0=1&W
usr-v32-p	USR Courier/Sportster V.32bis PCMCIA	57600	AT&F1&W
usr-v34-p	USR Courier/Sportster V.34 PCMCIA	115200	AT&F1S0=1&W
usr-v32	USR Courier/Sportster V.32bis	57600	AT&F1S0=1&W
usr-v34	USR Courier/Sportster V.34	115200	AT&F1S0=1&W
usr-spt-v32	USR Sportster V.32bis	57600	AT&F1S0=1S10=20S13.0=1&W0
usr-spt-336	USR Sportster 33.6	115200	AT&F1S0=1S10=20S13.0=1&W0
zyxel	Zyxel U1496E	57600	AT&FM0&D2S0=1S2=1

       Associating a Modem with a Port

  To automatically configure a modem and associate it in the modem table with the port it is attached to, use the following commands:

  Command> set  C0|all  modem-type  ModemName(short)
Command> reset  C0|all 

  For example; to associate a U.S. Robotics V.34 modem with port C0 and configure the modem, enter the following commands:

  Command> set  C0  modem-type  usr-v34
 Command> reset  C0 

  To configure all ports for the same modem type, use all  instead of the port number in the previous example. After the modem is attached to the port, configure the other modem settings described in "Configuring Ports for Modem Use" on page 10-5.

  To configure the modem not  to answer when users dial in, set C0=0  in the initialization string.

       Configuring Ports for Modem Use

  The modem settings described in this section are configured for each port and must match the configuration on the attached modem.

       Setting the Port Speed

  The speed of a port is defined as the DTE baud rate. The PortMaster allows you to specify three different baud rates for each port and one baud rate for host device ports. Port speeds are sequentially matched from the first baud rate through the third baud rate.

  For example, when a connection with this port is established, the PortMaster uses the first baud rate value to try to synchronize the connection speed. If no synchronization is possible, the PortMaster tries to synchronize speeds using the second baud rate value. If this fails, the third baud rate value is used. Each speed can be set between 300bps and 115200bps. The default speed is 9600bps.

  Modern modems and terminals must always be set to run at a fixed rate. To define a fixed rate, lock the DTE rate by setting all three speeds to the same value.

  To set the port speed, use the following command--entered on one line:

  Command> set  C0|all  speed  [1 |2 |3 ] Speed

  You can substitute any of the following for Speed:

300	1200	4800	19200	57600	115200
600	2400	9600	38400	76800

  You can set the speed for all the asynchronous ports simultaneously by using the set all speed  command.

       Setting Modem Control

  Set modem control on if you want to use the DCD signal for modem connections. When modem control is on, the PortMaster uses the condition of the carrier detect line to determine whether the line is in use. Modem control must be on for PortMaster outbound traffic. If modem control is off, the PortMaster assumes the carrier detect line is always asserted. As a result, the PortMaster cannot attach to the modem for outbound traffic because it regards the line as busy.

  To set modem control, use the following command:

  Command> set  C0 cd  on |off 

       Setting Parity

  The parity setting must be configured to match the parity setting on the attached modem. The parity default value is none  and must be used for ports configured for network dial-in or dial-out operation.

  Table 10-2 describes the parity options.

  Table 10-2 Parity Options

Option	Description
none	Assumes 8 data bits, 1 stop bit, and no parity bit. This is the default.
even	Assumes 7 data bits, 1 stop bit, and even parity.
odd	Assumes 7 data bits, 1 stop bit, and odd parity.
strip	Assumes 8 data bits and 1 stop bit. The parity bit is stripped from the data stream when it is received by the PortMaster

  To set the parity for a modem and its port, use the following command:

  Command> set  C0 parity even |none |odd |strip 

       Setting the Flow Control

  The PortMaster supports both software flow control and hardware flow control. Software flow control uses the ASCII control characters DC1 and DC3 to communicate with the attached device and to start and stop the flow of data.

  To set software flow control for a modem, use the following command:

  Command> set  C0 xon/xoff  on |off 

  Hardware flow control allows the PortMaster to receive data from the attached device by raising the Request to Send (RTS) signal on pin 4 of the RS-232 connector. The PortMaster sends information to the attached device only when the Clear to Send (CTS) modem line on pin 5 of the RS-232 connector is raised.

  To set hardware flow control for a modem, use the following command:

  Command> set  C0 rts/cts  on |off 

  Note ¯ Because it is more reliable, you should always use hardware flow control if it is available. Do not use both hardware and software flow control on the same port.

       Hanging Up a Line

  You can specify whether the DTR signal is dropped and the modem disconnected after a session is terminated. If line hangup is enabled and the session is terminated, DTR is held low, signaling the modem to disconnect. If line hangup is disabled, the DTR signal does not drop and the modem does not hang up when the user session terminates.

  To set line hangup for a modem, use the following command:

  Command> set  C0 hangup  on |off 

  Note ¯ Resetting the port administratively with the reset  command always drops DTR.