Monitoring Communications Equipment

Monitoring your communications equipment can help you identify the source of some common problems with your local modem or data circuit-terminating equipment (DCE) device, including the following:

• The modem or DCE does not answer incoming calls.
• The modem or DCE does not initiate outgoing calls.
• The modem or DCE initiates outgoing calls but does not successfully connect.

If the modem or DCE device cannot answer an incoming call or cannot initiate an outgoing call, you might need to reset it. Before resetting the device, check the following information:

• If the modem cannot answer incoming calls, check the AA (Auto Answer) light on your device. If it is off, reset the modem by using PPPCON or cycling the power.
• If the modem cannot answer incoming calls or initiate outgoing calls, use PPPTRACE to capture and decode modem or DCE device dialogs. Look at the send and receive exchanges to determine whether it is responding to the command properly (see the next section, Capturing Modem/DCE Device Dialogs ). If the modem does not respond properly, reset it by using PPPCON or cycling the power.

If the modem or DCE device can initiate an outgoing call but cannot connect, you might need to change the settings or the hardware. To determine your course of action, check the following information:

• Use PPPTRACE to capture and decode modem or DCE device dialogs. Look at the dial command to determine whether the correct phone number for the remote modem was used. If the number is incorrect, use NIASCFG to change the number.
• Use MONITOR to look at the serial signals. If data set ready (DSR) or data carrier detect (DCD) are off, the modem cannot connect. Check the cable between the router and the modem. If the cable is properly connected, try another modem. If this does not resolve the problem, enable the Simulate DSR On parameter. Load NIASCFG and follow this path:

  Select Configure NIAS > Protocols and Routing > Network Interfaces > Physical Options

This topic contains the following sections:

• Capturing Modem/DCE Device Dialogs
• Viewing Modem/DCE Serial Signals
• Resetting a Modem or DCE Device

Capturing Modem/DCE Device Dialogs

To capture and decode modem or DCE device dialogs, load PPPTRACE and complete the following steps:

1. From the Available Options window, select Configuration.

2. Select Capture Device.

   Select whether you want to capture the data to RAM or to Disk. If you select Disk, specify the filename in the Disk Filename field.

3. Press Esc to go back to the Available Options window.

4. Select Real-Time Monitor to view and capture the modem or DCE device dialog.

   The Real-Time Monitor window appears.

5. Press F7 to begin capturing the modem or DCE device dialog.

   Press F7 when you want to end the capture.

   You can also use the following keys:

   F2 ---Displays the statistics for the next interface.

   F5 ---Toggles the display between Hex and ASCII.

   F6 ---Enables you to freeze and resume the continuous display of data.

   F8 ---Goes to the next interface.

   F9 ---Returns to the preceding interface.

6. Establish the call.

   If you are testing outgoing calls, use CALLMGR on the local router to initiate the call. If you are testing incoming calls, use CALLMGR on the remote router to initiate the call.

7. Press F7 to stop the capture when the desired data has been sent.

8. Press Esc to return to the PPPTRACE menu.

9. Select Playback to view the captured data at your convenience.

   You can expect to see the response OK or an echoed command for each initialization string sent to the modem. If the modem does not respond, check the power and cable connections.

   Figure 3 shows a sample modem dialog.

   Figure 3
   Real-Time Monitor Capturing a Modem Dialog
   

Viewing Modem/DCE Serial Signals

To monitor the serial interface signals raised by the modem or the DCE device, load MONITOR and follow this path:

Select LAN/WAN Information > interface you want to view

Under the specific board's statistics section, look for serial interface signals such as DTR, DSR, RTS, CTS, and DCD (1=on, 0=off).

Resetting a Modem or DCE Device

To reset the modem or DCE device, load PPPCON and follow this path:

Select PPP Interfaces > interface you want to view > PPP Reset Modem > Reset Modem

The following information is displayed on the PPP Reset Modem window:

• Interface Name---Symbolic name used by the LSL to refer to this interface.
• Interface---Interface index used by SNMP to refer to this interface. This is the same as the board number assigned by the LSL to this interface.
• Reset Modem Results---Displays None if the test has not been run, Success if the modem reset correctly, Failure if the modem did not reset correctly, and In Progress if the test is in progress.
• Reset Modem---Pressing Enter on this field resets the modem or DCE device.