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US Robotics

Goedenavond! I am preparing to upload this musing from Amsterdam in The Netherlands. To do this, I connect to the Internet by dialing a local access number for my ISP's POP (for the acronym challenged, my Internet Service Provider's Point of Presence).Unfortunately, my connection speed is limited to--at best--33.6K, even though I am using a 56K modem. And therein lies part of the problem with 56K modems: they don't always provide 56K.

Like most larger hotels, mine here in Amsterdam uses a PBX (Private Branch Exchange) system for handling its telephone calls. Because of the PBX, the telephone signal gets converted between digital and analog several times. This translation means 56K modems cannot connect at 56K; they drop down to V.34 speeds (33.6K) because the 56K protocol requires that one end of the connection be completely digital, with just a single digital/analog conversion taking place at your modem.

When I say "protocol", you should be aware that there are two protocols currently competing to become a standard, perhaps by sometime in 1998. One the one hand, 3COM's US Robotics offers the "x2" protocol, using chips made by TI. On the other hand, everyone else (Rockwell, Motorola, Lucent) offers the "K56flex" protocol. Both can deliver 56K performance (well, nearly), but they are incompatible with one another.

There has been much discussion about which protocol will win in the end. In all likelihood the final standard will be a compromise between x2 and K56flex. The proponents of K56flex have shipped more than 80 percent of the chips currently in use in analog modems. But for now, my money's on US Robotics and x2 as the winner. I base this purely on marketing, not on the technical attributes of either protocol. When you walk into most computer stores you are greeted by mounds of US Robotics 56K modems. At the CompUSA in Pittsburgh they had a pile of modem boxes that was literally taller than I am. The K56flex modems are available, but they just don't have this type of in-your-face marketing going for them. US Robotics also has several full-page spreads in the popular press. The first article I read about K56flex was when they had to recall many of their modems when they first shipped due to quality problems.

In reality, a 56K modem can only provide a maximum connection speed of 53.3K. This is due to line voltage regulations imposed by the FTC, which makes "56K" a bit of a misnomer. When the x2 modems first came out, US Robotics took a lot of flack for what many consumers considered misleading advertising. The modems now carrier a sticker indicating that 53.3K is the maximum connection rate currently possible.

Still, 53.3K over POTS (Plain Old Telephone System) lines is pretty impressive. When I graduated from a 300 baud modem to a 1200 baud modem, I thought it was terrific. Later I used a 14.4K Sportster that I thought was fabulous. When modems speed reached 28.8K lines we were told "that was it". When the V.34 standard arrived, supporting 33.6K, we were told "OK, that's really it." No more bandwidth was possible through Ma Bell's POTS network. (They actually only have to guarantee a 4800 baud line, so you cannot complain very much about dirty lines.) Then came 56K.

56K modems achieve their seemingly impossible speed by changing the way signals are delivered over the network. Standard V.34 modems signals start out as digital bits which are then converted to analog tones for transmission over the telephone lines. When the data reaches the telephone company's central switch, it is converted back to digital form for transmission over their backbone. This conversion process limits connection speeds to about 35K using current technology. For 56K, the digital to analog conversion of data coming from your ISP doesn't take place until it reaches your telephone company's central office switch. This is possible because most ISPs are directly connected to one of the major Internet backbones via a digital router. This process eliminates the lossy analog to digital conversion. It still has a digital to analog conversion for transmission of data from the central switch to your modem, but a digital/analog conversion is not affected by line noise in the same way an analog/digital conversion is.

Note that 56K modems are asymmetric: the 56K speed only works from the Net to your modem, not vice-versa; you are still stuck with 33.6K as a the maximum upload speed. But since most Net traffic--such as browsing the Web---is mainly going down to your PC, and not the other way around, this tradeoff is not too bad.

Not all ISPs support 56K. If they do, they may support either the x2 protocol or the K56flex protocol, but not both. So it's important to select your ISP to match your modem, or the other way round if you haven't yet purchased a modem and want to stick with your current ISP.

Note: For those of you with an Andrew account at CMU, a new x2 56K PPP link is available at 683-5656.

But just checking your ISP is not enough; you have to check the quality of your telephone line too. Not all of them are capable of supporting 56K. Too much noise on the line means the increased digital traffic becomes too lossy and the protocol shifts down to lower speeds as needed. To see if your telephone line is capable of 56K speeds, use the US Robotics toll-free number 1-888-877-9248 to connect to their BBS. Log in as "Line Test". The system will perform some checks and inform you if your line is clean enough to support a 56K link.

Luckily, my telephone line at home passed the test. I routinely connect to my ISP at about 52K using an IBM 56K PC Card modem that supports the x2 protocol. Part of IBM's modem package is a 60-day free trial of the IBM Global Network, one of the largest ISPs around. I was previously using Netcom and had no complaints, other than their lack of 56K POPs. The IBM Global Network has over 500 POPs in the US, all but one of which supports the x2 protocol for 56K access. Outside of the US there are nearly another 500 POPs that IBM provides, far more than any other ISP that I know of. This becomes particularly important if you do a lot of travel and want to read email, access the Net, etc. while on the road. IBM does not charge any more for 56K access than for V.34 access. They have the usual $19.95/month for unlimited access. Other ISPs often charge extra and they have much more limited 56K support.

Also included with IBM's modem package, in addition to the modem itself and the free trial use of the Global Network, is VoiceType control, anti-virus software, a Web home page creator, and a nice feature that updates the dialing/connection software with patches or changes to the POP infrastructure automatically. The modem is also software upgradable to the new standard, whenever it might emerge. No matter which modem you choose, make sure it is upgradable to the new standard; this will protect your investment.

The fundamental question is, Are 56K modems worth it? In my opinion, yes. There are other options for high-speed Net access, such as ISDN, cable modems, xDSL, and satellite dishes. But they all have their own problems. ISDN is notoriously difficult to configure properly; the telephone companies themselves are often unsure of what to do. They are also much more expensive to use: most providers of ISDN charge a flat rate in addition to a per-minute connection fee. Cable modems and xDSL offer potentially much greater connection speeds, but their availability is severely limited at the moment. Satellite links such as Hughes DirecPC provide a fast downlink, but they too are pretty pricey. In a fairly recent development, Canada's Nortel announced a trial in the UK with a British partner offering approximately a 1Mb connection to the Net over the power grid; just plug it in and your connected! But the trail is also just that: a limited trial with an unclear pricing structure.

56K modems offer connection speeds that are nearly twice as fast as the current V.34 standard. I have found that using a 56K link feels nearly as fast as working on a LAN, especially for browsing the Web. With compression, the downloads can go up to four times faster than a a 28.8K connection. The biggest advantage of 56K modems over other high-speed access techniques is lower cost. Unlike ISDN, no new phone lines are needed; as long as your telephone line can pass the US Robotics line test, you're ready to connect at speeds approaching single-channel ISDN--but for the same $19.95/month flat rate that you're used to. As long as your ISP supports your modem's protocol of course. And you're not in a hotel...

Related information:

• The 56K modem page: www.56k.com
• US Robotic's x2 FAQ: x2.usr.com/technology/faqs.html
• Lucent's K56flex FAQ: www.lucent.com/micro/K56flex/k56faq.html

From Byte, C|Net, Internet World, PC Computing, PC Week, Inter@ctive Week, and other sources.

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