🚀 go-pugleaf

On Mon, 03 Mar 1997 07:58:52 -0800, Michael Dillon <michael@memra.com>
wrote:
>> > Almost all the
>> > ISP's are ramping up for X2 technology. 
>
>Not true. Most ISP's are *NOT* ramping up for X2 and will never support
>X2. That's because most ISP's use terminal servers with digital modems
>from manufacturers like Ascend, Livingston, Cisco, Computone, Microcom,
>and
>about a dozen others, that have all decided to support K56flex from
>Rockwell/Lucent. If you buy one of the many modem brands that will be
>supporting K56flex, then you will get true 56K connections to these
>ISP's.
>
>On the other hand, if you buy a USR X2 modem you will only be able to
>connect at 53K maximum to an ISP with USR TC terminal servers if you can

	FWIW Rockwell's K56Plus and the Rockwell/Lucent K56Flex
protocol will both also be limited to 53kbps, so far only the Lucent
v.2Flex protocol will allow for up to 56kbps connections with the
current FCC regulations on signal level, and even then connections of
more then 53kbps will be very rare.

>Some other factors to consider is that if there ever is an ITU standard
>for
>56K it is likely to be a lot closer to K56flex than X2 because X2 cannot

	The eventual standard will almost certainly be incompatible
with all the current 53/56k protocols.

>meet
>FCC (and presumably CRTC) regulations for power levels on the phone line
>unless it is clamped at 53K. On the other hand, K56flex can go up to 61K
>before it runs into the same problem.

	K56Flex runs into the exact same problems as USR's X2.

>Initial tests with X2 have shown that you don't get a 100% speed
>improvement over 28.8kbps. In some cases the increase in speed can be as
>low as 28% and
>these tests were done on uncongested networks.

	The same will apply with K56Flex.  K56Flex and X2 are actually
basically identicle protocols, with the only real differences being in
how they're negotiated.  Lucent has made some improvements over this
with their v.2Flex protocol, and those improvements may eventually be
incorporated in the K56Flex protocol, but there's no big difference
among all the various PCM protocols.

>As usual, new technology is for pioneers who don't mind getting their
>fingers burned and who don't mind finding out that their modem is
>obsolete next year when the standard is in place.

	Pretty much every company (including USR) is commited to
providing upgrades to the eventual standard when it becomes availible.
My advice to anyone looking to buy a 56k modem now is to get one which
will work with your ISP's hardware (meaning a USR modem if they've got
USR Total Control racks, a Rockwell based modem if they're using
Rockwell based modem racks, a Lucent based modem if they're using
Lucent based racks, etc.), and make sure that the modem has FlashROM
with a reprogrammable DSP, and will definately offer an upgrade to the
eventual standard.

Anthony Hill            | Sig files?  SIG FILES?!  What the
ahill@travel-net.com    | hell do I need a sig file for?!