Check phone outlet and cables, call waiting, and line quality
Make sure your phone outlet or "jack" works by connecting a telephone to it. If it works, check the connection between the outlet and your computer. Disconnect and reconnect the cable to be sure that it is firmly inserted. If you are using an external modem, check the connection to your computer and its power cord. Be sure cables are not cut, chewed, or otherwise damaged. If you experience frequent or random disconnection, consider these possible causes:
- Disconnect if idle for __ minutes enabled?
You may have set your computer to automatically disconnect from the Internet after a period of inactivity. Check your PPP Options:
- Open System Preferences.
- Click Network.
- From the Show menu, choose Internal Modem.
- Click the PPP tab, then click PPP Options.
Be sure this is not your issue before spending time troubleshooting your phone line. Similarly, your Internet service provider may automatically disconnect you when you are idle. Ask your Internet service provider what its idle disconnection policy is.
- Call Waiting
If you have call waiting, your Internet connection may be interrupted by an incoming call. Check your phone book or with your phone company for help turning off call waiting on a per-call basis. In North America, you usually just add "*70" to the dial-up number. Enter this code as a prefix followed by two commas when typing your ISP's dial-up phone number in Network preferences. For example, if your dial-up phone number is 555-1111, enter "*70,,5551111" as your dial-up phone number. The commas create a pause between tones, allowing the code prefix to be acknowledged before dialing.
- Phone off the hook
See if others in your home or office are trying to use the same line.
- Environmental interference
It's possible that your phone line receives interference from a strong electrical field, or an electric or radio appliance. Try a phone jack in another area or remove potential sources of interference, if possible.
- Phone line quality
Analog phone lines ("POTS," or plain old telephone service) are generally maintained for voice quality. Your modem may reveal quality issues with your phone line that are not considered when evaluating for voice quality, and that are not perceptible to the human ear. If frequent disconnects cannot be isolated to another cause, you may need to investigate phone line quality by contacting your telephone company. If you cannot resolve an issue with phone line quality, consider other alternatives that may be available in your area, including cable, DSL, ISDN, satellite service, and so forth.
For an expanded discussion of this subject matter, see "Troubleshooting Phone Line Issues That Affect Modem Connections".
Don't use the Ethernet port!
Your computer's Ethernet and modem ports look alike, but the Ethernet port is wider. On many Macintosh computers, it's possible to plug a standard RJ-11 phone cable into the Ethernet port, though this has been prevented on some models. Be sure to connect your phone cable to the modem port. Notice the similarities and differences in these two ports, which have identifying icons:
Check connection settings
Check four things in Network preferences: that the modem is your primary network interface, your dial-up account information, your TCP/IP settings, and your modem settings. Follow these steps:
- From the Apple menu, choose System Preferences.
- From the View menu, choose Network.
- Choose Active Network Ports from the Show pop-up menu ("Advanced" from the "Configure" pop-up menu prior to Mac OS X 10.1).
- Be sure that the checkbox for "Internal Modem" (or another modem) is selected.
- Drag Internal Modem to the top of the Port Configurations list to make it the preferred, or primary, network interface.
- Choose Internal Modem from the Show pop-up menu.
- Click the PPP tab.
- Check the Account Name and Telephone Number fields to be sure you have correctly entered the information your ISP gave you.
- If you choose to save your password, retype it to be sure it is correct.
- Click the TCP/IP tab. Follow your ISP's instructions for setting up this pane. For more information, see "Mac OS X: How to connect to the Internet with PPP (dial-up access)".
- Click the Modem tab. In the Modem pop-up menu, be sure you have selected a modem script that matches your modem.
- If your telephone exchange is limited to either Tone or Pulse, be sure that the radio button selected next to "Dialing:" matches your exchange.
- If you subscribe to voicemail service that lets you know when you have a message with a "beeping" dial tone, deselect the checkbox for "Wait for dial tone before dialing."
- If you have made any changes, click Apply Now.
Get the latest software
Under certain circumstances, your modem may need a software update in order to work. If you have an Apple built-in modem, be sure you have the latest update for the version of Mac OS X that you are using, and that you have installed any applicable modem updates for your computer model. Search Apple Downloads using the word "modem" and the model name of your computer. If you have a third-party modem, check the manufacturer's website for possible modem script, driver, or firmware updates.
Get help from your ISP
If you have not resolved the issue with the steps above, contact your Internet service provider.