openers, a neighbor’s wireless phone system, television sets, and nearby
antennae for radio and television stations and government and military
installations. You may be able to obtain devices that are more resistant to
outside interference or find other places to install your phone systems.
Certain advanced features offered by phone companies can cause dropped
connections for dial-up modems. Principal among these is call waiting; some
modems are unable to deal with the tone that is sent to indicate another
incoming call. More advanced modems can be instructed to ignore momen-
tary breaks in the data stream. (You can also temporarily turn off call waiting;
consult your phone company for instructions. You may be able to add one-
time disabling each time you initiate use of your dial-up modem.)
Sometimes even what appears to be a properly functioning telephone jack
may cause some problems because of reversed polarity;a standard telephone
may work, but the modem may become confused. If you suspect this, you can
purchase an inexpensive telephone polarity tester from Radio Shack or other
electronic parts suppliers. If you find reversed polarity, the solution is to
remove the phone jack from the wall and swap the connection points of the
red and green wires (for line 1) or the yellow and black wires (for line 2).
Is the problem with the port built in to the laptop itself?
There could be an electrical problem, or a conflict of system resources. Using
current versions of Windows, the easiest way to check for this is to go to
Control Panel➪System icon➪System Properties➪Hardware tab➪Device
Manager. Check the Ports (COM & LPT) and the Universal Serial Bus con-
trollers in search of conflicts and use the troubleshooting tool to attempt to
fix them. Ports are used by POTS, DSL, and cable modems, so a failure here
can knock out any external communication device.
Troubleshooting an internal dial-up telephone modem................
As I’ve noted, there are three types of internal modems. Each comes with its
own trials and tribulations:
Built-in to the motherboard or attached directly to it on a mini circuit
board. These are the most difficult to get to, requiring the nearly complete
disassembly of the laptop case, and they may be impossible to repair or
replace. After you have satisfied yourself that this problem is not with a
device driver or system resources, work around the failed hardware by
attaching an external modem to the USB port or a PC Card slot.Installed into a special access slot on the bottom of the laptop case. This
connection is sometimes called a mini-PCI slotand should work with any
brand of device designed to its specifications. These tiny circuit boardsChapter 15: Modems: The Essential Translators 235