Internal Modems faster then external serial modems?

Internal Modems faster then external serial modems?

Post by Tim Kiddl » Sat, 02 Oct 1999 04:00:00



My question is, are internal 56Kbps modems faster than external serial port
connected 56Kbps modems, when transferring highly compressible files.

The question is not relevant to USB connected modems.

I have tested a cheap internal modem and a mid-priced external modem.  The
external modem was connected at 115200bps and so was the internal modem, but
I suspect the DTE speed means nothing for an internal modem.  The operating
system is NT4 sp5 on a Pentium II, 300MHz.

The line speed for the internal modem was 50,667bps.
The line speed for the external modem was 52,000bps.

Using a 300KB dBase file, the throughput, using FTP, was:
Internal, 19.2KBytes/s, i.e., at least 153,000Kbps.
External, 11.2KBytes/s, i.e. at least 89,000Kbps.

The internal modem is running at faster than the DTE speed, which is why I
think that may be irrelevant in the configuration for that type of modem.
Since 115,200 is as fast as I can connect the external modem on my serial
port, it seems that internal modems will perform better on compressible
files.

Any thoughts or comments on these results?

Thanks

Tim Kiddle

 
 
 

Internal Modems faster then external serial modems?

Post by John Nava » Tue, 05 Oct 1999 04:00:00


[POSTED TO comp.dcom.modems]


>My question is, are internal 56Kbps modems faster than external serial port
>connected 56Kbps modems, when transferring highly compressible files.

>The question is not relevant to USB connected modems.

>I have tested a cheap internal modem and a mid-priced external modem.  The
>external modem was connected at 115200bps and so was the internal modem, but
>I suspect the DTE speed means nothing for an internal modem.  The operating
>system is NT4 sp5 on a Pentium II, 300MHz.

>The line speed for the internal modem was 50,667bps.
>The line speed for the external modem was 52,000bps.

>Using a 300KB dBase file, the throughput, using FTP, was:
>Internal, 19.2KBytes/s, i.e., at least 153,000Kbps.
>External, 11.2KBytes/s, i.e. at least 89,000Kbps.

>The internal modem is running at faster than the DTE speed, which is why I
>think that may be irrelevant in the configuration for that type of modem.
>Since 115,200 is as fast as I can connect the external modem on my serial
>port, it seems that internal modems will perform better on compressible
>files.

>Any thoughts or comments on these results?

1.  Real world data is almost never compressible enough for a 115 Kbps
serial port to be a bottleneck.

2.  When software compression is used, true for many (most?) ISP's, the
issue becomes moot in any event.

3.  The DTE speed does matter for an internal modem with a real UART.  It
doesn't matter for certain types of virtual ports.  You can't generalize.

--
Best regards,
John Navas     <http://navasgrp.home.att.net/>
    28800-56K Modem FAQ: <http://modemfaq.home.att.net/>

 
 
 

Internal Modems faster then external serial modems?

Post by eelder » Mon, 20 Dec 1999 04:00:00


I don't think the results are statiscally significant. Professionals prefer
external modems.


Quote:> My question is, are internal 56Kbps modems faster than external serial
port
> connected 56Kbps modems, when transferring highly compressible files.

> The question is not relevant to USB connected modems.

> I have tested a cheap internal modem and a mid-priced external modem.  The
> external modem was connected at 115200bps and so was the internal modem,
but
> I suspect the DTE speed means nothing for an internal modem.  The
operating
> system is NT4 sp5 on a Pentium II, 300MHz.

> The line speed for the internal modem was 50,667bps.
> The line speed for the external modem was 52,000bps.

> Using a 300KB dBase file, the throughput, using FTP, was:
> Internal, 19.2KBytes/s, i.e., at least 153,000Kbps.
> External, 11.2KBytes/s, i.e. at least 89,000Kbps.

> The internal modem is running at faster than the DTE speed, which is why I
> think that may be irrelevant in the configuration for that type of modem.
> Since 115,200 is as fast as I can connect the external modem on my serial
> port, it seems that internal modems will perform better on compressible
> files.

> Any thoughts or comments on these results?

> Thanks

> Tim Kiddle

 
 
 

Internal Modems faster then external serial modems?

Post by Hooda Ges » Mon, 20 Dec 1999 04:00:00





>> I don't think the results are statiscally significant. Professionals
>prefer
>> external modems.

>What survey is this statement based on? A true professional would know that
>there are situations where internal modems are preferrable and situations
>where external modems are preferrable and be able to determine which was
>required in a particular situation.

Define "professional". I mean, I know a young lady who couldn't care less
what kind of modem is used and yet she's a professional. :)

Seriously, the odds are that externals are more often used in business
evironments. The reasons for this are that the units are simpler to
troubleshoot and then, if needed, replaced. Hardware resets of the externals
(ie, power cycling), which often clear problems, are easier and do not
require the computer to be rebooted.

But, as you say, it depends on the situation. In many cases, internal modems
will perform perfectly well. So I tend to agree, there's nothing to prove
that "professionals" prefer them.

Hooda

 
 
 

Internal Modems faster then external serial modems?

Post by Kerry Kopper » Tue, 21 Dec 1999 04:00:00



Quote:> I don't think the results are statiscally significant. Professionals
prefer
> external modems.

What survey is this statement based on? A true professional would know that
there are situations where internal modems are preferrable and situations
where external modems are preferrable and be able to determine which was
required in a particular situation.



> > My question is, are internal 56Kbps modems faster than external serial
> port
> > connected 56Kbps modems, when transferring highly compressible files.

> > The question is not relevant to USB connected modems.

> > I have tested a cheap internal modem and a mid-priced external modem.
The
> > external modem was connected at 115200bps and so was the internal modem,
> but
> > I suspect the DTE speed means nothing for an internal modem.  The
> operating
> > system is NT4 sp5 on a Pentium II, 300MHz.

> > The line speed for the internal modem was 50,667bps.
> > The line speed for the external modem was 52,000bps.

> > Using a 300KB dBase file, the throughput, using FTP, was:
> > Internal, 19.2KBytes/s, i.e., at least 153,000Kbps.
> > External, 11.2KBytes/s, i.e. at least 89,000Kbps.

> > The internal modem is running at faster than the DTE speed, which is why
I
> > think that may be irrelevant in the configuration for that type of
modem.
> > Since 115,200 is as fast as I can connect the external modem on my
serial
> > port, it seems that internal modems will perform better on compressible
> > files.

> > Any thoughts or comments on these results?

> > Thanks

> > Tim Kiddle