Fax Modems / Fax Switches Fax modems are a popular item for computers. They are modems that can send and receive faxes as well as data. There are some interesting details that you should be aware of. These modems can be internal or installed inside your computer or external, a box that sits along side of or on top your computer. It seems that the most popular one is the internal unit, although I personally like external modems more. The internal one goes on a card slot inside the computer and there are no connecting cables or boxes to get in the way. Its just there and you plug in the phone cable to the rear of it at the slot. There is a new problem that has come up since the release of the Pentium computers. Pentium computers have 64 bit PCI slots and 8/16 bit ISA slots. There are usually 4 of each. Older 486-386-286 computers usually had 8 slots. The problem arises because you are limited to only 4 ISA slots and many owners already have them filled up. One for the CD ROM, one for the sound card, one for the scanner card, and the last one for a tape drive card. In the event your modem was in first, you might not be able to install that particular tape drive with its board although there are alternatives such as parallel port tape backups or slower tape drives that don't use cards. I like an external modem because I can see the lights that indicate progress and status of the call. I can hear the built in speaker better too. I can also move the modem to another computer or use it at a friends house. But that's me. An external modem usually costs more than an internal modem unless you have it installed professionally. It requires a simple cable to connect to the external COM port. You should also be aware that most computers do not come with high speed serial ports and this may be a problem if you want an external modem. Internal modems can be a nightmere to install or run. Computers usually have 4 communication port addresses and 2 interupt channels that are available. Computers usually come with 2 COM ports assigned as COM 1 and COM 2. You mouse usually plugs to COM 1 and COM 2 is left for your external modem. If you install an internal mode, you must not be on the address of the internal modem. COM1 is 3F8 and IRQ4. COM2 is 2F8 and IRQ3. COM3 is 3E8 and IRQ4. COM4 is 2E8 and IRQ3. As you can see, the interupt channels are shared. This means if your mouse is on COM1, your modem can't go on COM3. Most good modems can go on COM4 and that would solve the problem, right? Wrong! Some modems and their software won't work on COM 4. Others have trouble getting modems to work on COM4 in Windows. Windows will work on COM4 if you know how to set it up. You must go into the Control Panel in the Main Group and start with COM 1, then COM2, them 3, and then 4. The advanced settings must actually show the address and interupts. Do not leave them at the "default" setting. That's where it goes wrong. You can test everything with Terminal in the Assessories Group. Select setup communications and set to Com 4, then set your speed. Type AT at the modem prompt. You should get an OK. Save the settings as Terminal.TRM. The most practical for some is to disable the COM2 that comes with your computer system and set the modem up on COM2. The problem here is you need to find the paper work that came with your computer for jumper settings to disable COM2. If you think all this is too complicated, someone listened. Newer internal modems can be purchased as "plug and play" where there are no jumpers to set. The process is done electronically by software. Unfortunately, plug and play is new and has its problems. Many different board manufacturers are going to plug and play and one manufacturer's software will reset another manufacturer's equipment and render it inoperative. Your fax modem may not do what you want. You can not send a copy of an invoice or receipt to someone. You can only send typed documents that you compile in your computer. You could if you bought a scanner and scanned the document in and then converted it to a fax document. That becomes a real chore. You also have to leave your computer turned on to receive faxes. That draws alot more power than a fax machine and you will notice a difference in your electric bill. You also must set up the software so that it prints to your printer if it is turned on or you may not realize you have a fax received and stored in your computer. One of the biggest problems relating to fax modems and fax machines alike is that they need their own phone line. Do NOT rely on fax switches. Fax switches require the CNG tone from the calling fax machine to activate the switch to determine that its a fax call. Most fax fachines do not put out this tone. The switch will never operate. The best solution is a second line or IDENTA RING from Bell. This assigns a second phone number to the telephone wires and it rings with 2 short rings. A separate box separates the ring reliably.