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To: Frank A. Coluccio who wrote (3747)	5/17/1999 1:21:00 AM
From: Bernard Levy	Read Replies (3) \| Respond to of 12823

Hi Frank: You are correct on the 52 Mb/sec figure for VDSL. On cable modem downstream capacity per channel, while it is true that the DOCSIS 1.0 standard yielded about 30 Mb/sec, the next generation will allow easily 40 Mb/sec (note that the downstream standard will allow 256-QAM). The current TERN modem uses S-CDMA to spread either QPSK or 16-QAM in both the upstream and downstream directions and have a capacity of only 14 Mb/sec. HOwever modems based on BRCM's chips already go to about 30 Mb/sec downstream. The bottom line is that I take it for granted that 40 Mb/sec will be the downstream cable standard. You are right that there is still a 25% increase when one goes to 52 Mb/sec, but the main point remains that one 6 MHz cable channel = (approximately) one VDSL line. Cable defenders usually make the point that for DSL the shared medium is moved upstream, but detailed specifications of the fiber capacity needs of the local loop to support DSL service have been worked out in detail. Some providers may be offering DSL service right now without having upgraded their COs and local loop accordingly, but when the ILECs start rolling out DSL service systematically, this is one thing they will handle carefully. Best regards, Bernard Levy