Troubleshooting "No Dial Tone"
Topic
When the modem cannot detect or successfully
acquire a dial tone, the connection attempt will fail, and Apple
Remote Access will respond:
Or, when using the bundled America Online 4.0:
Use the troubleshooting path in this article to help identify the
source of the problem.
Note: While this article specifically mentions iMac, it is
applicable to the PowerBook G3 Series (Bronze keyboard) and Power
Macintosh G3 (Blue and White) as they use a variation of the iMac
modem.
Discussion
Before beginning, ensure that the modem hasn't been silenced, which
wouldn't otherwise affect its functionality, but may be misleading.
To confirm, and to prepare for the troubleshooting that follows,
turn the computer volume up in the Control Strip or the Monitors
& Sound control panel. Increasing the volume will automatically
uncheck the "Mute" button in Monitors & Sound. If
no system beep is heard, troubleshoot for a no computer sound problem
first.
Troubleshooting Path
Between steps, close/quit any open control panel or application,
saving changes as necessary.
Step 1
Verify Physical Connectivity
Check the telephone line connection at the wall outlet and the modem
port. Ensure that it is not connected to the ethernet port by mistake.
Push firmly in on the connectors at both ends, or disconnect and
reconnect them, to seat them securely.
NOTE: This modem is incompatible with digital/PBX phone lines.
If an ordinary, residential, consumer telephone has worked in the
same outlet, it is a compatible analog line.
Step 2
Configure Modem Control Panel
Configure the Modem control panel as shown. Selecting the wrong
modem script can cause this symptom. It doesn't matter whether modem
firmware updates have been applied or the V.34 modem script selected.
Step 3
Configure Remote Access and Test
Open the Remote Access control panel. Enter a name (user ID), password,
and telephone number.
Inaccurate entries will not prevent detection of a dial tone; however,
if a prefix like "9" must be dialed to reach an outside
line, enter it before the telephone number, followed by a comma
as shown.
Click "Connect" and listen for a dial tone, number tones,
or handshaking (squealing sound). If heard, or if the "Status"
field ever shows "Starting PPP," "Starting network
protocols," "Communicating at 24000 bps," or any
other such indicator that appears after acquiring a dial tone, the
problem is fixed.
If it is convenient to perform step 12 (test the line with a telephone),
do so now; otherwise, proceed through the steps in order.
This step is repeated in steps 5, 7, 9, 11, 13, and 14.
Step 4
Configure Extensions Manager For Mac OS Only
Open the Extensions Manager control panel. Select "iMac All"
or "Mac OS 8.5 All" from the pop-up menu shown. Future
Mac OS revisions will introduce other name or version changes but
the correct "All" choice should be clear.
Ensure that iMac Modem Extension is among the enabled extensions
listed (enabled extensions show an "x" in the adjacent
checkbox).
Close Extensions Manager and restart the computer. Any extensions
that might have captured the modem for their own use (commonly fax
or telephony extensions) are now disabled and will remain so until
enabled in Extensions Manager again.
Step 5
Retest
Open the Remote Access control panel. Click "Connect"
as in step 3. Watch and listen.
If it's fixed, the offending extensions can be further isolated
via extensions troubleshooting and, if necessary, proper configuration
of the software that used those extensions.
Step 6
Disable Dial Tone Checking
Open the Modem control panel. Click the "Ignore dial tone"
checkbox to enable it. Remote Access will no longer check for a
dial tone before dialing out, proceeding instead as if one is present.
Step 7
Retest
Open the Remote Access control panel. Click "Connect"
as in step 3. Watch and listen.
IMPORTANT: Because "Ignore dial tone" is enabled,
it's possible that only the number tones will be heard as dialing
occurs, but not the initial dial tone or modem handshaking. Typically,
the "modem is not responding properly" alert will then
appear. If so, the problem persists.
If it's fixed, the problem was due to the unique characteristics
(volume or frequency, for example) of this dial tone as delivered
through the analog line. There are three options:
- Leave "Ignore dial
tone" enabled.
- Experiment with cleaning
up the telephone signal by hardware-isolating the telephone
line as per step 13.
- Call the telephone company
to have them check the lines, though they may already be as
clean as they're realistically going to get.
Finally, disabling dial tone checking will usually work around the
problem posed by some voice mail services that notify the user of
waiting mail by altering the dial tone or inserting a series of
tones before it.
Step 8
Reset Parameter RAM
Though the fax, telephony, and other 3rd party extensions were disabled
in Extensions Manager, certain Chooser settings they might have
established could still reside in PRAM.
Reset the Parameter RAM: shut the computer down, then power it on
and immediately press "Option-Command-P-R" (four keyboard
keys, all pressed together), keeping them pressed until the computer
startup chime repeats at least once after the initial chime.
Step 9
Retest
Open the Remote Access control panel. Click "Connect"
as in step 3. Watch and listen.
If it's fixed, the problem was a conflicting setting in Parameter
RAM, probably created by one or more of the disabled extensions,
either because it was involved in a system crash, is in conflict
with other extensions or with the Mac OS, or was not configured
correctly. Perform extensions troubleshooting, but keep in mind
that the problem may not immediately (or ever) return, even after
turning 3rd party extensions back on.
Step 10
Perform AT Command Troubleshooting
AT command troubleshooting speaks more directly to the modem using
a terminal emulator and the Serial comm-toolbox tool. By bypassing
Remote Access, it addresses the possibility that Remote Access has
become damaged.
There are a variety of shareware and commercial terminal emulators
available, any of which would suffice, but the following steps will
make use of software bundled with the iMac.
Open AppleWorks or ClarisWorks (different names for the same program),
select a Communications document, and click "OK." If an
alert says that no terminal tools are available, reinstall the program
from the iMac Install CD.
A blank, untitled communications document (terminal window) should
now appear. Choose "Connection" from the Settings menu
to open the Connection Settings window.
Choose "Serial Tool" from the "Method" pop-up
menu. The other settings should be correct by default, but ensure
that "Internal Modem" is selected. Click "OK."
Choose "Open Connection" from the Session menu:
Now proceed as shown below. Enter AT&F, ATDT, and ATDT [telephone
number].
Note the clock in the upper-left corner of the document window:
it must be advancing. If it is not advancing:
- Repeat the previous AppleWorks
steps, starting with the Settings menu.
- Quit and restart AppleWorks,
then repeat the previous AppleWorks steps.
- Reinstall AppleWorks.
- Skip to step 12 and continue
down from there.
Important: If the clock is advancing and no characters appear
in the terminal window as you type, the computer can't see the modem
at all. This can mean:
- Another application or
extension is using the modem. If the previous troubleshooting
steps were correctly followed, this possibility has been eliminated.
- The modem is dead, unseated
from its internal socket, or some other internal hardware failure
has occurred. This conclusion cannot be drawn until all the
software possibilities are exhausted. There's only one left:
- The system software is
corrupt.
Read these 3 options carefully, then choose one:
- If a dial tone was acquired
using AT commands, proceed to the next step.
- If characters could be
entered but no dial tone was acquired, skip to step 12 now.
- If no characters could
be entered in the terminal window, skip to step 14 now.
Step 11
Trash Preferences
Because AppleWorks can obtain a dial tone but Remote Access cannot,
locate and trash "Modem Preferences" and "Remote
Access Connections," located as follows:
- System Folder : Preferences
: Modem Preferences
- System Folder : Preferences
: Remote Access : Remote Access Connections
Then repeat steps 2 and 3. If it still doesn't work, it could be
argued that the Remote Access components alone have become corrupted
and require reinstallation, but because they have thus far allowed
themselves to be opened and configured, performing step 14 now is
preferred.
Step 12
Verify Cable & Outlet
Disconnect the telephone cable from the modem and plug it into a
telephone, then listen for a dial tone with the telephone receiver.
If a dial tone cannot be heard, there is a problem with the outlet
or the cable. Try a different cable and outlet.
IMPORTANT: It doesn't matter that a telephone used to work on the
wall outlet at some time in the distant past, or that it worked
there while using a different telephone cable. Unless the outlet
and the cable were tested with a telephone just prior to connecting
the iMac to the same cable and same outlet, this must now be done.
Arriving directly from step 3? Go back.
Step 13
Hardware-isolate Line
Establish a point-to-point, single-cable connection between the
modem and the wall outlet, isolating the line from all other devices,
including telephones, answering machines, fax machines, and even
caller-ID boxes, cable extenders, and line splitters (pictured).
Thus, the configuration should be: iMac modem > telephone cable
> wall outlet. The shorter the telephone cable, the better. Then
retest as per step 3, using the Remote Access control panel.
If that works, one or more of the removed devices was hurting the
line quality (thus affecting the dial tone) or pushing an already
poor line past the breaking point. There's not much that can be
done except attach those devices to different outlets or experiment
with other devices, cables, splitters, and combinations thereof.
Sometimes the inside or outside home wiring is at fault, requiring
an experienced telephone technician to diagnose.
Remove any splitters and other devices and connect directly to the
wall outlet.
Step 14
Clean Installation
Perform a clean installation of the operating system. Instead of
manually disabling the existing System Folder, start up from the
Apple Restore CD. Then use Apple Software Restore, confiqured at
its default settings to perform a clean installation.
Then repeat steps 1 & 2 to retest.
If the problem is fixed, you are done.
If the problem continues, the iMac will
probably need service. But first, you may wish to re-enable the
old System Folder:
1. Start up from one
of the two orange system CDs.
2. Drag the System Folder at the root level of the hard drive to
the Trash (the whole folder).
3. Open the "Original Items" folder at the root level
of the hard drive. Locate the System Folder within and drag it on
top of the hard drive icon, replacing the one just moved to the
trash. Then open and close the System Folder to ensure it becomes
blessed. A blessed System Folder is represented by the happy Macintosh
icon superimposed on the System Folder icon. Restart, and manually
eject the system CD after the startup chime.
4. The "Original Items" folder still retains all of the
applications that originally shipped with the computer. Each will
have a freshly installed duplicate outside of the "Original
Items" folder. Either the duplicates or the originals may be
removed, but be careful not to throw away any of your own documents
or other items that might have been saved to any of those locations.
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