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2 way satellite broadband or any other rural solutions?


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[quote]There is no difference between a like-for-like internal and external modem, in fact pretty much all modems on the market rely on a tiny number of internal chips that actually do the conversion. Though...[/quote]

That's wrong. Internal Modems and USB ones are just bits of tone generating/decoding hardware driven by the computer itself ; that's why they are erratic, because Windows isn't up to it.

Get an External RS232 Serial Modem ; that does all the work and simply sends a datastream to your PC. They are a little more expensive ( a few euros ) but vastly superior to the other types.
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[quote]I write music for films and I am always receiving and sending big files (average 30 Mb) so Broadband is useful. I could camp out in the nearest Cybercafe in Chateau Chinon but the missus would leave m...[/quote]

ISDN will only give you 128kps upstream max, so it'll still take the best part of an hour to send a 30Mb file.

Could I suggest one possible solution ; stop sending 30Mb files - this depends *what* you are sending of course, but if you are sending music send them as MP3 format - 30Mb could be an hour or so.

This might be a dim question, but you are zipping or bz2ing the files before transmitting them ?
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>rather special circumstances involving particular modems, particular ISPs and particular compression systems

That would be pretty much any modem sold in the last two years (V92 standard), any ISP worth its salt, and the compression scheme used by default.

i.e. if you have a new or less than 2 year old computer, just plug it and and connect to most ISPs (not Wanadoo interestingly, which is where I found out about this), and browse the web you will probably be suffering if you have an external serial modem as compared to an internal modem.

>The assumption being that an internal modem will be on a PCI slot or better and that most serial ports on PCs are throttled at 115kbs.

Practically all internal modems are PCI these days, right? Also do not dismiss external USB modems which do not suffer from the problem. And last time I looked your default PC serial port was throttled at 115kbs, even the UART (serial chip) capability to go faster.

> I don't think that the issue of getting slightly better speed on some types of file transfer is of much interest to most people

50-100% faster on web pages. I am quite surprised you can dismiss that so easily.

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Practically all internal modems are PCI these days, right?

Some use proprietary risers.

Also do not dismiss external USB modems which do not suffer from the problem.

I do dismiss USB modems but for other reasons. They are not very reliable and, as with internal modems, rely heavily on the processing power of the PC. The software drivers are often very odd indeed.

And last time I looked your default PC serial port was throttled at 115kbs, even the UART (serial chip) capability to go faster.

I'm sorry but I don't understand this sentence.

50-100% faster on web pages. I am quite surprised you can dismiss that so easily.

I doubt that the actual speed increase in real life is as high as that. And I still believe that for most users the improvement in general connection stability makes using an external modem worthwhile, if people are having trouble with a built-in one. If they aren't having trouble there is no need to worry, of course.

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>>And last time I looked your default PC serial port was throttled at 115kbs, even the UART (serial chip) capability to >go faster.

>

>I'm sorry but I don't understand this sentence.

Most serial ports, even on brand new motherboards with the latest processors are controlled by 16550 compatible serial chips, which don't go above 115kbs. There are 16550-like chips that can go faster but as far as I'm aware are only found on specialized serial cards and require specialized drivers or setting a registry key to up the speed.

Apparently the maximum theoretical speed of a new (i.e. V92/V44 modem) is about 300kb/s (sounds reasonable, 56.6x6x8/10), so using an external serial modem will throttle the maximum speed to 40% of that.

>I doubt that the actual speed increase in real life is as high as that.

That is something that would need to be put to the test properly, but I certainly noticed a big performance boost in general surfing speed with a V92 USB modem over a V90 serial modem on the same ISP (yes I have one) before I switched to ISDN. As part of my job I have to review random lists of web pages.

Don't get me wrong I understand your concerns about winmodems and I have always kept a serial modem as a backup. I think the benefits in cost and performance outweigh the drawbacks.

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>Serial Modems are limited to 56 kbps ; give or take a bit. You can't get 300kb out of one.

I'm not sure I understand you. Only the line speed is limited to 56kbs with a 56K modem. With compression the data throughput rate from one end of a modem to the modem on the other end can theoretically reach 300kbs for text files - a compression ration of 6:1 for text or HTML files is very achievable, after accounting for stop and parity bits.

The DCE rate (between modem and computer) is generally limited to 115 kbs maximum as I described above and would in that case be a bottleneck.

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>Serial Modems are limited to 56 kbps ; give or take a bit. You can't get 300kb out of one.

Here are some real life test Winmodem results showing more than 300kb/s (newgroup updates), and 170kb/s for a very, very ordinary web page.

http://groups-beta.google.com/group/comp.dcom.modems/browse_frm/thread/c0767c4dc4bffc22/9f8d8a8603a2f0e6#9f8d8a8603a2f0e6

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I will continue to recommend external serial modems for simplicity and reliability in cases where an internal modem is broken, missing or doesn't connect reliably (assuming that the line is in good order, of course). Serial modems have the advantage of always working well with no driver problems or installation issues.

Obviously anyone who is happy with their internal modem does not need to look for a replacement.

Any speed calculations that are based on the theoretical 56k maximum modem speed are doomed to failure. Modems rarely get past 45k in the field and I don't think I've ever seen one get to 50k.

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I agree. I think the duff point with the compression routines is that virtually everything that is hefty copying - music, video, pictures, programs - is usually compressed before you start, so compression won't get you much of an improvement. About the only thing that will effectively compress is raw text or HTML.
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