This will be an overview of the requirements to use a 56KFlex modem. It will include an overview of the existing standards and for our part a conservative recommendation on your purchasing options.
Currently, there exist two competing standards for 56K technology. On one side is X2, which is supported by US Robotics. On the other side is Kflex, which is supported by Ascend, Lucent, Rockwell, Motorola and other manufacturers. We support the Kflex standard, but it also is not the final standard. Sometime this year the standard will become official and final. What that means is that any modem you purchase must come from a store with a good return policy so that if you have problems, you are not stuck with a limited use modem. Any time a new standard comes out, the rush to sell new modems sometimes means that "less than fully functional" models find their way to the store shelves. If you have trouble with your new modem purchase, don't take it back to the store immediately; first call the manufacturer to obtain tech support. It is likely that with the new modems your software will require special settings to make the new modem work. It is common for the manufacturer to have released new firmware updates that improve the function of existing modems; usually these are available as files you can upload into the modem flash-bios. If you can't make the modem work satisfactorily after all that, then return the modem to the store you bought it at.
Because of FCC power transmission limits, X2 will be effectively limited to 53K. K56flex is not affected. This isn't a big problem, as most people probably would not connect at the full 56K anyway, due to phone line limits that prevent many people from connecting at 28.8 or 33.6K. The FCC does not limit modem speeds, it does limit the amount of power that can be sent through the phone line in order to prevent interference with other telephone circuits.
A 56K connection isn't 56k both ways, it's faster for downloads than for uploads. Downloading means receiving data from another computer such as downloading files or pulling down a Web Page. During downloading data is changing from a digital signal to an analog signal. Digital-to-analog conversions are perfectly accurate; so speeds up to 56K are possible. When uploading, data is changing from an analog signal to a digital signal. Analog-to-digital conversions are imperfect, so noise is introduced into the signal. The noise is in the form of mathematical rounding errors. These errors can accumulate if the analog-to-digital conversions are repeated (as is sometimes the case in some telephone networks).
Another requirement that can prevent some people from using 56K is that you can only have one analog-to-digital conversion between your home or office and the Internet service provider (us). This is also called a hop. If there's more than one, you can't use 56K, and your connection will be limited to V.34 speeds (a maximum of 33.6K). With two a-to-d conversions the peak speed is around 33.6k, with three a-to-d conversions the limit is around 28k, with 4 a-to-d conversions the limit is around 24k, and so on. In most circuits, 6 a-to-d conversions are the maximum you will ever see, limiting connections to around 14.4k. Fortunately we see few a-to-d conversions in San Marcos, however other nearby areas such as Austin and San Antonio see higher numbers of them. If your office is on a PBX, you may have symptoms similar to adding a-to-d conversions to the circuit path.
A rule of thumb that holds true most of the time is this: If your current modem can connect reliably at its full speed, then buying a new K56Flex modem will possibly improve your speed further. However if your current modem connects at a speed below its rated maximum speed, then there is nothing to gain by buying a faster modem. Unless your modem is faulty, a slower than maximum connection speed indicates that you are having your connection speed limited by the condition or design of your telephone line. This is why if you buy your new modem and see no speed increase, you should take it back and get your money refunded. That is where the generous refund policy of the store you shop in is so important.
Information inside your computer is in binary, a series of 0's and 1's. Phone lines are analog, they transmit data as a series of peaks and valleys. This is the wave pattern that many people have seen on electronic test equipment screens. A "modem" is a MOdulating/DEModulating device; it modulates outgoing sound from digital to analog, and demodulates incoming data from analog to digital.
Above a certain level the signal-to-noise ratio of any medium becomes too low to reliably transfer data. The analog phone line (copper wire) is the limiting factor in the speed of data transmission because of the inherent noise it contributes.
A lot of the telephone network is increasingly digital. Our part of the phone connection between the phone company and us is digital. Digital lines still have noise, and are still subject to limitations, but they have less noise and a higher limit. Generally speaking, the digital connections are designed to be error-free and nearly perfect, allowing us to completely avoid a-to-d conversions between the telco and us.
Because the standard hasn't been set yet, you'll have to be content with the proprietary 56K protocol that we offer: K56flex from Rockwell and Lucent. Dozens of hardware manufacturers have chosen this protocol. We went with the majority opinion of 80% that figure that the 56Kflex protocol will either be closest to the official standard or that will be easiest to upgrade to the official standard.
So here are the simple facts, we are confident that until the 56K standard becomes official we are going to support the 56Kflex standard. It is closest to what we think the standard will be. We have invested time, money and effort to provide this access to you for your use before the official standard comes out. We suggest that if you purchase a 56K modem, you should purchase a 56kflex modem, it will work with our hardware and software. You should purchase a modem from a store that has a good return policy or that provides a means to upgrade via free download to the official standard. If you choose an X2 modem it will still work with our equipment but only at a 33.6K speeds. An X2 modem should be purchased with the same criteria in mind, namely that they have a return policy if you have any difficulty connecting to Realtime or that it will be software upgradeable to the official standard.
The other choice is to simply wait till the standard becomes official and then purchase a modem that adheres to the standard. This option has always been available, as each new modem speed/standard has come out. We will be there for you either way; our service will work with the 56Kflex standard and will work with the official standard shortly after it is ratified. Just so you know, the founders of Real/Time communications are telephony engineers that have experience designing and implementing hardware and software involving data communications. We have been members of modem standards committees in the past, and have a great deal of experience in these issues. So we bring you this information from the point of view of those that truly understand what it means and how to best take advantage of the information. We want you to have the best possible chance of having your next modem purchase be the right one for you, with you getting the best possible use from your investment.
