Modems And Connections Essay, Research Paper
The issues discussed here often overlook the very basic things you need to get a modem connection – if you’ve never used a modem, or you are doing a new installation, you may want to seek more basic help and troubleshooting information first. There are MANY factors that affect modem connection speed. A 33.6 modem will rarely get 33.6 connections (it requires a very clean line and clean routing to the server modem); 28.8 and 26.4 are more common. Similarly, a 56k modem will rarely get 56k – most people are getting 42-49.3k; a lucky few are getting rates in the low to mid-50’s. The large group that is getting no 56k, or rates below 40k is the focus here. Low (*40k) rates can indicate a digital impairment that is not correctly compensated for by modem firmware. It can also be related to the quality of your modem and premises telephone wiring. Other devices (phones, answering machines, fax, etc.) plugged in to the same line (even though not in use) can also cause lower speeds. If the impairment is at the ISP or specific to the routing to that ISP, you may be able to get higher rates calling other #s (ISPs). And problems can also be related to the type of equipment and firmware in the modems you are calling.
The way many of us use modems has changed dramatically in the last few years: Today, the vast majority of our connections are to a single local ISP access number as opposed to calling many (local and toll) BBS and information providers. Effective troubleshooting must isolate the problem, and part of my approach calls for checking connections with as many servers as possible.
As used herein, 56k refers to dial-up modems operating faster than v.34 rates. V.34 allows up to 33.6k connections (although 33.6 is rare; 28.8 is the more common maximum you will get with v.34). The lowest Flex, x2 and V.90 rate is 28000 (most 56k modems will not connect at a lower than 32k initial rate before reverting to a v.34 connection). And before you start with the steps below, make sure you have your modem installed correctly, and set the port speed (”maximum speed” in Control Panel-*Modems-*Properties) to 57,600 or 115,200.
Call Waiting & Your Modem
Many of today’s modems can recover from significant line noise hits – including the call waiting tone that you may get if you have the call waiting feature on your line.
If you have call waiting, in most areas, you are able to disable it prior to placing a call by dialing a code (usually *70) before dialing your ISP’s number. If a person tries to call you while you are on the net, they will get a busy signal.
If you don’t disable call waiting and your modem doesn’t disconnect on the call waiting tone, the caller will hear your phone ringing and ringing and ringing.
You might be able to get your modem to disconnect on call waiting tone by lowering the modems disconnect on loss of carrier register. Consult your modem documentation for the register and values. Most modems use S10 for the disconnect on loss of carrier with a value of 7(msec); you could try a lower value (down to 1) by adding s10=# in extra settings. Similarly, if you’re getting bumped when a call comes in and you want the modem to stay connected, you would increase the value.
What’s a 56k-compatible line? (New 2-Mar-99)
One of the requirements listed on at least one brand of 56k modems is “A 56k-compatible line” – without defining what such a line is.
Pretty slick. It’s true that some telephone lines/facilities will prevent 56k from working, but there is no way for the average member to easily determine whether his line is ‘56k-compatible’!
If you get a 56k modem, and you get 56k connections, you can safely say that you (presently) have a 56k-compatible line. However, if you don’t get 56k connections, you cannot correctly assume that your line is not ‘56k-compatible’.
Possible reasons for not getting a 56k connect can include:
The firmware in your modem isn’t working properly for your line conditions
The firmware in your modem isn’t ‘compatible’ with the firmware in the server modem you are calling
The firmware in one of the modems isn’t ‘compatible’ with the digital portion of the telephone network being used
Your line is not ‘56k-compatible’
In some of the above circumstances, you would be able to achieve a 56k connect with a different modem, or calling a different V.90 server.
56k Modem manufacturers have generally defined a ‘56k-compatible line’ as being one that has only 1 D/A conversion (or 1 A/D conversion), and your local loop is less than 3? miles. You may be able to get an answer – not always correct – if you ask your telco for the loop length and if your line has more than 1 A/D conversion. There is no ‘requirement’ or standard procedure for getting this information from a telco. But, even if you find you have only 1 A/D conversion (a ‘56k-compatible line’), you may still not be able to get a 56k connect with any 56k modem if your telco introduces certain types of digital impairments.
What 56k Connect Rate Should You Expect?
56k Modems rarely connect close to 56k. In the US, FCC-imposed power give most 56k modems a maximum potential for a 53.3k connection. This was supposedly lifted for V.90 modems now that an international standard is out and has been embraced.
But, what happens in the real world? These are my estimates of what’s happening (Sep ‘99) with 56k modem connections:
About 60-70% of 56k modem owners are getting 56k connects (rates higher than 33.6k). 30-40% get rates of 33.6k or less.
Of those getting 56k rates, 80-90% are getting 40k or higher.
About 75% get rates between 44-49.3k.
About 10% get rates of 50k or higher, and about 15% get rates between 34.6 – 38.6k.
However, the throughput achieved by a substantial portion of the connections doesn’t match the connect rate.
Of the 30-40% of 56k modem owners not getting 56k connects, about 15% are connecting at 31.6 – 33.6k, 70% at 26.4-28.8k, and 15% at 24k or lower.
The rate achieved depends upon a number of factors including:
The Modem (sometimes the one you have won’t work with your line conditions/ISP)
The Modem Firmware/driver (sometimes a firmware upgrade/downgrade will yield improvement)
Your line conditions (sometimes the facilities provided by the phone company prevent 56k connects)
The ISP’s Modems (sometimes your modem won’t achieve 56k-interoperability with your ISP’s 56k modems)
The ISP’s Modem Firmware (sometimes an ISP modem firmware upgrade will yield improvement)
What is DSL?
DSL (digital subscriber line) is a proven technology that takes advantage of standard copper telephone lines to provide secure, reliable, high-speed Internet access. Unlike traditional dial-up connections such as analog modems and ISDN, DSL delivers continuous “always on” access. That means multimedia-rich websites, email, and other online applications are immediately available to you, anytime. And Covad? DSL makes it possible for you to remain online even while you’re talking on the telephone – without jeopardizing the quality of either connection.
DSL is available in a spectrum of speeds. Some are best for home use, while others are designed to accommodate rigorous business demands. Whether for business or the home, DSL offers unsurpassed price/performance value compared to other online access options.
For Business:
Originally, companies seeking high-speed connectivity looked to T1 lines as a solution. However, dedicated T1 lines cost as much as $2,000 a month to maintain. Now, Covad DSL provides continuous T1 level performance (as fast as 1.5 Mbps to download files), at a fraction of typical T1 costs.
For Home:
DSL is also a legitimate option for home users. At about $2 a day for DSL service that meets the needs of most home-based users, fast Internet access is priced well within your reach
DSL isn’t available everywhere yet. However, as the leading specialist in DSL-based Internet access, Covad is moving rapidly to deploy its services across the entire U.S. By the end of 1999, Covad’s digital network will be accessible to 2.8 million businesses and almost 30% of U.S. households. And this aggressive expansion is expected to continue into the next century.
Here are the five facts you should know about DSL Internet access. This service is:
Remarkably fast
With DSL service, you can benefit from Internet speeds that are up to 12 times faster than a typical ISDN connection and 50 times faster than a traditional 28.8 Kbps modem. This means that in the 12 seconds it takes to read this information, you could have downloaded a 2 megabyte presentation file or web photograph. It would take 10 more minutes (600 more seconds!) to download the same file with a traditional 28.8 Kbps modem.
Highly reliable
You can depend on DSL because its proven technology takes full advantage of the existing telecommunications infrastructure. And you can count on DSL to scale with your future connectivity needs. That’s a level of comfort you won’t find with other Internet access technologies.
Inherently secure
Because our DSL network provides a dedicated Internet connection via private telephone wires, you can bypass dial-up intruders or shared network hackers. Unlike traditional dial-up modems or cable modems, DSL protects your valuable data with the most secure connection available.
Surprisingly affordable
DSL is widely recognized as the most cost-effective connectivity solution for small businesses. Covad DSL delivers industrial-strength T1-like speed (as fast as 1.5 Mbps) to multiple users at only 25% of typical T1 costs. There’s no better price/performance option available.
DSL is also an exceptional value for home users. At about $2 a day for service that meets the needs of most people, Covad’s basic home configuration is priced within everyone’s reach.
“Always on”
DSL is ready to run, every minute of every day. There’s no more logging on and off, no more busy signals or disconnects. This gives you the freedom to focus on what you want to accomplish online – rather than focusing on trying to get connected. In fact, you can be more productive because the power and immediacy of the Internet is continuously available at your fingertips.
ISDN
Integrated Services Digital Network. ISDN provides standard interfaces for digital communications networks and is capable of carrying data, voice, and video over digital circuits. ISDN protocols are used worldwide for connections to public ISDN networks or to attach ISDN devices to ISDN-capable PBX systems (ISPBXs).