128K Vs. 56K Modems

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56K Modems:

At 1 time, every1 thought that 28.8K & 33.6K would be the end of the line. The main problem is the disturbance of the analog telephone lines. To get higher speeds, you’d need radically different modems that wouldn’t work over standard phone lines.

The advent of 56K modems has changed all that. You can now have a faster connection using your existing phone lines & new modems that work just like your old modem, only faster.

The nature of 56K technology is a little different than existing analog modems. In particular, it depends on a half-digital connection to achieve its higher speeds. Because of the lager number of digital lines, the disturbance still exists but at a lower level so it has become possible to transfer data with a maximum speed of 56 kbps.

Technology:

To understand 56K, it’s necessary to take a brief look at how traditional analog modems work.

Information inside your computer is in digital format: all of the data is stored as 1s and 0s. Normal phone lines are analog: they transmit data as a series of peaks & valleys. The’modem’ is a MOdulator/DEModulator: it modulates outgoing data from digital to analog, and demodulates incoming data from analog to digital.

Above a certain threshold(called Shannon’s Limit) the signal-to-noise ratio of any medium becomes too low to reliably transfer data. The analog phone line is the limiting factor in the speed of data transmission because of the inherent noise it contributes.

Today’s telephone network is increasingly digital. In particular, the portion of the phone connection between the phone company & the Internet Service Provider(ISP) is often digital. Digital lines still have noise, & are still subject to Shannon’s limit, but they have less noise & a higher ceiling.

Several companies have created techniques that take advantage of the digital portion of the phone network to achieve higher speeds than were possible with a purely analog pathway. These new techniques treat the phone system as a mostly digital network that just happens to have an analog portion.

There are several consequences to the reliance on a half-digital connection. Your Internet service provider(ISP) must have digital phone lines to the public switched telephone network(PSTN). That’s the easy part: if your ISP offers 56K, they’ve got the digital lines.

Advantage:

1. The normal telephone lines can be used.

   
   




2. Some of the existing modems can be updated.

   
   




3. Max. download speed: 56 kbps.

   
   




4. Max. upload speed: 33, 6 Kbps.

   
   

Disadvantage:

1. Problems because of interferences.

   
   




2. Phone charge has still to be paid.

   
   

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128K Modems(ISDN):

ISDN is the high-speed access technology of choice for home users & small to medium businesses. Nothing else is as widely available, economical, or mature. The hardware, lines, & Internet access are all available today, & millions of people are already taking advantage of it. ISDN is already an ITU standard, so there’s no need to fret over looming standards wars or patent lawsuits.

One huge advantage of ISDN is that one ISDN line has two phone lines with two phone numbers. You can surf & use the phone at the same time. Practically all consumer ISDN hardware has a port for plugging in analog phone equipment(telephones, fax machines, etc.) so you can use your analog equipment over the digital line. You can even plug your modem in for calling services that don’t support ISDN.

Technology:

Speed Consumer ISDN has two 64K bearer(B) channels & one 16K delta(D) channel that acts as a controller. You can use 1 or both B channels for surfing, for speeds of 64K or 128K(in some areas, the speeds are 56 and 112). Because the lines are digital, there is very little noise, & you’re assured of getting a connection at the full speed.

So, ISDN is faster then the 56k-technology & much more resistant against disturbance & failures. ISDN is standardized world wide & accepted by the greatest part of the Internet providers.

Advantage:

1. No problems because of interferences.

   
   




2. Max. download speed 64 kbps;  using both lines 128 kbps.

   
   




3. Max. upload speed 64 kbps; using both lines 128 kbps.

   
   




4. Supported by all the providers.

   
   




5. Proved technology.

   
   




6. Two phone lines.

   
   

Disadvantage:

1. An ISDN connection has to be installed.

   
   




2. An ISDN adapter is necessary.

   
   

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My Advice

ISDN(128K) IS A BETTER CHOICE COMPARED TO A 56K MODEM. WELL THE OTHER THING IS THAT MAKE A CHOICE ACCORDING TO UR NEEDS.