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Strings
Guest
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 Posted: Sun Apr 08, 2007 3:08 pm Post subject: 90 kbps brick wall |
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is there any modem (mass market v.92) which does not have the 90 kbps
cap? (8/9 of 115 kbps)
since i'm hitting 90 kbps on text, it seems to be the limiting factor.
m. |
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Strings
Guest
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| Posted: Sun Apr 08, 2007 5:41 pm Post subject: Re: 90 kbps brick wall |
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Strings wrote:
| Quote: | is there any modem (mass market v.92) which does not have the 90 kbps
cap? (8/9 of 115 kbps)
since i'm hitting 90 kbps on text, it seems to be the limiting factor.
m.
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well i see some business modems that are 230 kbps. pricey.
m. |
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Floyd L. Davidson
Guest
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| Posted: Sun Apr 08, 2007 7:45 pm Post subject: Re: 90 kbps brick wall |
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Strings <strings@example.net> wrote:
| Quote: | Strings wrote:
is there any modem (mass market v.92) which does not have the
90 kbps cap? (8/9 of 115 kbps)
since i'm hitting 90 kbps on text, it seems to be the limiting
factor.
m.
well i see some business modems that are 230 kbps. pricey.
|
The extra bucks probably will not gain a significant increase
data transfer rate.
If you are getting 90kb/s with a 115kb/s port speed it appears
that you are limited by compression, not by the port speed.
Otherwise you'd be "hitting better than 110kbps".
It might be that for some very small percentage of time
compression could be higher, but it will max out at something
less than 150kb/s peak, and that will only happen on very rare
occasions. Thus it is very likely that if you move to a modem
which supports a port speed of 230 kbps the affect you'll see on
data transfer rate is to go from 90kb/s to 92kb/s...
--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@apaflo.com |
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Aaron Leonard
Guest
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| Posted: Tue Apr 10, 2007 4:59 am Post subject: Re: 90 kbps brick wall |
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~ >> is there any modem (mass market v.92) which does not have the
~ >> 90 kbps cap? (8/9 of 115 kbps)
~ >> since i'm hitting 90 kbps on text, it seems to be the limiting
~ >> factor.
~ >> m.
~ >
~ >well i see some business modems that are 230 kbps. pricey.
~
~ The extra bucks probably will not gain a significant increase
~ data transfer rate.
~
~ If you are getting 90kb/s with a 115kb/s port speed it appears
~ that you are limited by compression, not by the port speed.
~ Otherwise you'd be "hitting better than 110kbps".
115200 bps port speed gives 11520 chars/sec hence 11520*8 = 92160 bps.
~ It might be that for some very small percentage of time
~ compression could be higher, but it will max out at something
~ less than 150kb/s peak, and that will only happen on very rare
~ occasions. Thus it is very likely that if you move to a modem
~ which supports a port speed of 230 kbps the affect you'll see on
~ data transfer rate is to go from 90kb/s to 92kb/s...
One option is to go with a (shudder) Winmodem (preferably one
with a hardware DSP). I've measured 400kbps sustained with
a Cisco AS5400 -> Agere winmodem (V.90 + V.44), transferring
artifically highly compressible text payload.
Aaron |
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Strings
Guest
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| Posted: Sun Apr 22, 2007 7:55 pm Post subject: Re: 90 kbps brick wall |
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"Aaron Leonard" <Aaron@Cisco.COM> wrote in message
news:bgkl13tjs6fkk2u3oehjh6tvh8mnd87jcc@4ax.com...
| Quote: | ~ If you are getting 90kb/s with a 115kb/s port speed it appears
~ that you are limited by compression, not by the port speed.
~ Otherwise you'd be "hitting better than 110kbps".
115200 bps port speed gives 11520 chars/sec hence 11520*8 = 92160 bps.
|
i assumed that 8N1 would be 8/9 of 115,200. but i don't know much about
serial I/O.
TCP overhead could explain why i'm right at 90.
| Quote: |
~ It might be that for some very small percentage of time
~ compression could be higher, but it will max out at something
~ less than 150kb/s peak, and that will only happen on very rare
~ occasions. Thus it is very likely that if you move to a modem
~ which supports a port speed of 230 kbps the affect you'll see on
~ data transfer rate is to go from 90kb/s to 92kb/s...
One option is to go with a (shudder) Winmodem (preferably one
with a hardware DSP). I've measured 400kbps sustained with
a Cisco AS5400 -> Agere winmodem (V.90 + V.44), transferring
artifically highly compressible text payload.
|
i will try a Winmodem. i will have to get a PC with pci slots.
i also use linux, so i'll buy an external too.
m. |
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Strings
Guest
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| Posted: Sun Apr 22, 2007 7:57 pm Post subject: Re: 90 kbps brick wall |
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thanks Floyd and Aaron.
i will do research on which ISPs have v.44. |
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Michael R N Dolbear
Guest
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| Posted: Mon Apr 23, 2007 1:06 am Post subject: Re: 90 kbps brick wall |
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Strings <strings@example.net> wrote
[...]
| Quote: | a Cisco AS5400 -> Agere winmodem (V.90 + V.44), transferring
artifically highly compressible text payload.
i will try a Winmodem. i will have to get a PC with pci slots.
i also use linux, so i'll buy an external too.
|
Last time Linux and controllerless modems were discussed there was a
Linux driver for at least one of these so I suggest you check before
you buy an external modem.
--
Mike D |
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Strings
Guest
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| Posted: Mon Apr 23, 2007 2:12 am Post subject: Re: 90 kbps brick wall |
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"Michael R N Dolbear" <me@privacy.net> wrote in message
news:01c7850a$87bb1360$LocalHost@default...
| Quote: |
Strings <strings@example.net> wrote
[...]
a Cisco AS5400 -> Agere winmodem (V.90 + V.44), transferring
artifically highly compressible text payload.
i will try a Winmodem. i will have to get a PC with pci slots.
i also use linux, so i'll buy an external too.
Last time Linux and controllerless modems were discussed there was a
Linux driver for at least one of these so I suggest you check before
you buy an external modem.
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i have 2 external modems already, but i want a v.92. i like externals for
non-windows, non-linux operating systems.
upgrading to cable modem would solve my problem. :-) |
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Strings
Guest
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| Posted: Mon Apr 23, 2007 2:13 am Post subject: Re: 90 kbps brick wall |
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"Michael R N Dolbear" <me@privacy.net> wrote in message
news:01c7850a$87bb1360$LocalHost@default...
| Quote: |
Strings <strings@example.net> wrote
[...]
a Cisco AS5400 -> Agere winmodem (V.90 + V.44), transferring
artifically highly compressible text payload.
i will try a Winmodem. i will have to get a PC with pci slots.
i also use linux, so i'll buy an external too.
Last time Linux and controllerless modems were discussed there was a
Linux driver for at least one of these so I suggest you check before
you buy an external modem.
--
Mike D
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i've seen v.92 externals for $20 new! i don't know how they compare to a
Zoom or USR.
thanks for the info. |
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Aaron Leonard
Guest
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| Posted: Mon Apr 23, 2007 11:26 pm Post subject: Re: 90 kbps brick wall |
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~ > 115200 bps port speed gives 11520 chars/sec hence 11520*8 = 92160 bps.
~
~ i assumed that 8N1 would be 8/9 of 115,200. but i don't know much about
~ serial I/O.
"8" is databits, "N" is No (0) parity bits, "1" is stop bit. 8+0+1 = 9,
but this misses the START bit. 1 start bit + 8 data bits + 0 parity bits
+ 1 stop bit = 8 (data bits) / 10 (total bits).
~ TCP overhead could explain why i'm right at 90.
Yep.
Aaron |
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