[net.dcom] modem evaluation - Telebit Trailbla

lindahl@ti-csl (04/29/86)

>>since 9600 baud modems are supposed to be just around the June corner
>>at about $700 each, or so the salescritters would have me believe.)

>I've seen the CDS V.32 full duplex 9600 over dialup modems but they
>are about $3500. Also, they are sync only, although you can get
>converters I assume.

Another source for 9600 baud: MICROCOM, whose 300/1200/2400 baud modems
I recently selected for a moderately-sized dialup application (about 150
dialin users) also makes a 300/1200/2400/9600/19.2 modem for ~ $1800
(retail). Advantage to me is that I can upgrade my 2400 baud  modems 
up to the 9600 baud variety for the difference in price between the 
two modems (or so I am told). They run in either sync or async mode, 
but ARE NOT true V.32 (rather , they are V.22 with MICROCOM's MNP 
error-correction protocol). 

Charlie Lindahl
Texas Instruments (CRL/CSL)

ARPA:  lindahl%TI-CSL@CSNet-Relay
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DISCLAIMER: As in "Mission Impossible", the secretary will disavow any 
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phil@portal.UUcp (Phil Sih) (05/02/86)

In article <4000001@ti-csl>, lindahl@ti-csl writes:
> Another source for 9600 baud: MICROCOM, whose 300/1200/2400 baud modems
> I recently selected for a moderately-sized dialup application (about 150
> dialin users) also makes a 300/1200/2400/9600/19.2 modem for ~ $1800
> (retail). Advantage to me is that I can upgrade my 2400 baud  modems 
> up to the 9600 baud variety for the difference in price between the 
> two modems (or so I am told). They run in either sync or async mode, 
> but ARE NOT true V.32 (rather , they are V.22 with MICROCOM's MNP 
> error-correction protocol). 
> 
> Charlie Lindahl
> Texas Instruments (CRL/CSL)
> 

I have seen ads for these products and even seen a demo of MNP at a
Microcom seminar but have no real data on how they actually perform
in real situations.  Have you measured the actual throughput you are
getting from the modem?  I understand the Microcom modems all use a 
2.4 kbps link but to get the higher throughput rates employ various
forms of compression.  This being the case I find it quite difficult to 
believe they could reliably produce a 4:1 compression or better to do
9.6 or 19.2 kbps.  

On the other hand I have heard of people getting well in excess of 
10 kbps using the Telebit modems and NO compression.  If you have some
experience with the Microcom products it would be interesting to 
hear it.  Which modems to use is going to be an ongoing interest here.