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Technology Stocks : Westell WSTL

WSTL 6.470

+6.4%

Jan 26 3:56 PM EST

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To: jefferson who wrote (6289)	9/12/1997 8:18:00 PM
From: bill c.	of 21342

To ALL: Ok.. back from a business trip. Zero announcements from Westell this week.... high volume.... stock up 2 points. It reminds me of the pending news from Bell Atlantic... 2 or 3 weeks before BA announced the stock moved up. John Hunt - Interesting news on Nortel and their ATM switch being sold to BT. I'm still expecting a Fujitsu/Westell partnership for BT. What else can we talk about tonight... Oh.. I read on the AMTX thread that Japan can't use ADSL with ISDN. Someone better tell Westell not to ship their modems for that Japan trial. The real question is if the present T1E1.4 DMT standard will allow ADSL to start above the ISDN frequency. ISND or POTS over under ADSL This would enable both a legacy ISDN service and an ADSL service to be delivered over the same line. This requires the ADSL spectrum to be moved up from around 25 to 30 kHz to a much higher frequency. From VDSL splitter design studies looking to overlay VDSL on ISDN or POTS it is deduced that it may be possible to design a splitter which would start the DSL signal at around 300 kHz in order to have minimal impact on ISDN reach with minimal splitter complexity. Given that ADSL currently only operates up to a maximum of around 1MHz (and on long lines DMT rarely uses spectra above 600 kHz) there would be very little capacity left for the ADSL signal. Hence ADSL range reduction would be very significant. However, if it is possible to design a splitter that could locate the ADSL signal from around 140 kHz and above, this would be sufficient to allow both 2B1Q and 4B3T ISDN to pass through it. The subsequent impact on ADSL range would be less severe with only a few hundred meters range reduction. It remains to be seen whether such a splitter can be built having this lower starting frequency for ADSL and at the same time having little impact on the performance of ISDN or POTS. This sort of experimental evidence will be needed to confirm the viability of this option...... ISDN only under ADSL Range performance implication. ADSL spectra must be moved up from a 10 - 40 kHz lower band edge to start at around 140 kHz. Splitter design is simpler than option 2 since only ISDN impedances need to be matched, not POTS impedances which are complex in some operators networks. The range is expected to reduce by a few hundred meters. There could also be a problem in that standardised DMT ADSL relies on a pilot tone at 76 kHz for timing synchronisation. Hence some silicon may not work in this configuration. It is likely that both ANSI compliant DMT designs and existing CAP designs would require re-working to accommodate the base-band ISDN. The proposals to ETSI [references 1,2,3 & 4] for future work on ADSL to examine the ideas presented in options 2 and 3 need to assess these issues.....

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