INSTALLING A MODEM
| Installing an internal modem is considered one of the most difficult upgrades that one can undertake. | |
| External modems are much easier to install, assuming that the modem or serial port isn't faulty in any way. The same cannot be said of internal modems: even if you have Windows plug and play, the odds are stacked against you that you will experience more problems installing it than you would with any other component. | |
| The term modem is derived from modulator/demodulator, referring to how the modem works, taking the digital output from the computer and transforming (modulating) it into tones that can travel along analog lines. (e.g Telephone lines) | |
| When these tones are received by another modem, they are demodulated back into digital form. A FAX machine works in a similar way, but the output is directed to a printer. | |
| Modems are serial devices, which means they can send or receive only one bit of data at a time. | |
| Parallel devices (such as printer and scanners) are capable of sending and receiving several bits - usually 8 bits of data at once. |
| The rate at which modems transfer information is measured in Kilobits per second (Kbps). The latest protocol is V90, or 56Kbps. | ||||||||||||||||
| When purchasing a new modem, buy a V90 enabled and try to avoid Winmodems or cheap unknown devices, stick to the well known brands such as 3Com/US Robotics, Pace, Xircom. IMPORTANT LATE NEWS; Hayes are in receivership and the modem drivers for the V90 (UK) 56k voice modem are NOT available | ||||||||||||||||
| Remember that it depends upon the modem at the other end of the link, usually your ISP that will determine the maximum throughput of data. If the ISP is still using a 33Kbps modem and you have a 56Kbps modem, you will not achieve anything greater than up to 30Kbs. Even with a V90 enabled modem and a V90 ISP, you will only get up to around the 52Kbs, and that's if you have a perfect link and live very close to the local telephone exchange. (NB: The baud rate is frequently confused with the data transfer rate, which is true a slow speeds. Strictly speaking, the baud rate is the number of voltage or frequency changes that can be made in a second). | ||||||||||||||||
| The main advantage of choosing an internal modem is that you don't need to worry about the UART (Universal asynchronous receiver transmitter) that governs data transfer through your serial port. A 56Kbps modem requires a 16550 UART, this is built in to an internal modem. | ||||||||||||||||
| Once you have decided on a modem, find a free 16 - bit ISA slot and remove the back plane, (the modem only uses an 8 - bit slot). Gently but firmly push the modem in, and use the retaining screw to hold it in place. | ||||||||||||||||
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If you are using Windows 95/98, you may be very, very lucky - your operating system will autodetect the autoplay device and instal the necessary drivers without any prompting from you, as well as configuring COM ports and IRQ settings. If you are using Windows 3.x, you will have to experiment with the settings. |
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ADDRESSING THE ISSUE
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| The above table shows that the COM port can share interrupt request lines, so that COM3 may share the same IRQ as COM1, and COM4 as COM2. | ||||||||||||||||
| However, each port also needs to be given its own memory address. If you are using Windows 95, you can configure these settings as follows: | ||||||||||||||||
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However, each port also needs to be given its own memory address. If you are using Windows 95, you can configure these settings as follows: START-----> SETTINGS-----> CONTROL PANELS-----> SYSTEM-----> DEVICE MANAGER-- PROPERTIES then RESOURCES for the COM ports |
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In Windows 3.x, these are set from: MAIN---> CONTROL PANEL--->PORTS--->SETTINGS--->ADVANCED |
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| IF THE PLUG AND PLAY HAS NOT FOUND THE CORRECT MODEM | |
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Make sure you have the modem driver disk available: (1) Click START--->SETTINGS--->CONTROL PANELS--->MODEMS (Double click) IF the Window shows Standard Modem or the incorrect modem The correct modem driver software has not been installed |
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| Windows will incorrectly identify the modem and will tell you it has detected a STANDARD MODEM.Regardless, insert the driver disk and click on "Have Disk". | |
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Enter A:\ (Your floppy drive) in the "Copy manufacturers files from" box and select your modem from the list. |
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| Click OK | |
| Click FINISH | |
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