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Technology Stocks : LAST MILE TECHNOLOGIES - Let's Discuss Them Here -- Ignore unavailable to you. Want to Upgrade?

To: D. Newberry who wrote (5276)	9/17/1999 12:37:00 PM
From: MikeM54321	Read Replies (1) \| Respond to of 12823

"As for your voice calls, you have a 24x7 connection to the central office switch at all times, so your telephone operates the same whether you are connected to a modem or not." D. Newberry, Thanks for your reply and welcome to the Last Mile. Can you clear up one more thing for me. Doesn't the twisted copper pair run into the DSLAM line card from the customer side and out the back comes two sets of wires. One goes to a traditional voice circuit-switch, and the other goes to a data packet switch? In other words, I thought this was precisely where the data traffic was separated from the voice traffic. This allows the very expensive voice switch to be freed up from long winded data sessions. If this is correct, doesn't this mean that the DSLAM line card will be tied up by a DSL user who is online, when another neighborhood DSL user simply wants to make a voice call? The reason I'm asking this is because I don't see that the telco can save much money by disconnecting a DSL user when he is not using the service. Because, as we know, data users tend to tie up the line for something like 10-20 times longer than a voice call. If this is the case, that means the telco has to buy so much hardware anyway that they might as well offer a, one-to-one, always on connection when all is said and done. Thanks, MikeM(From Florida) PS This is all leading somewhere, but first I want to make sure I'm on the right track.

To: D. Newberry who wrote (5276)	9/18/1999 5:31:00 AM
From: John Stichnoth	Read Replies (1) \| Respond to of 12823

D.N.--Thought I understood this, but your exchange with MikeM has me wanting to get a picture of the physical layout into, in and out of the CO. Is this correct?: Our little twisted pairs each arrive at a central office, where they are attached to a voice switch. Out the back of the voice switch, wires connect to the voice network and other wires connect to the data network, the first connection being the 28.8 modem, or DSLAM or whatever (depending on the service being provided to the customer). (Note: a T1 line would presumably bypass the voice switch). Being connected to the DSLAM does not mean you are connected to the internet, because the DSLAM has to assign a modem before you are connected. Some DSLAM (e.g., g-lite) products can do this dynamically, i.e., connecting you when you first request something off the internet, and disconnecting you when you are idle. This dynamic connection is similar to the POTS computer connection line, and presumably the length of time before you are knocked off can be set or changed by the provider as part of the software, at the provider's discretion. If a customer decides to change services, for instance from dsl to some other data service option, a physical change would normally be needed to be made within the CO--i.e., a technician would have to go and physically move the wires on the back end of the voice switch from the 28.8 modem to the other data service option, e.g., the dslam. (Parenthetically: At least some of "dedicated T1" service installations these days seem in fact to be HDSL. These allow the telco to run the second copper pair to an HDSL switch (avoiding the voice switch?). This saves the telco from having to run a more robust (fiber?) line from the customer's premises to the CO or T1 pickup point.) It seems therefore that the telco would save some money in installation and maintenance if the data line could always be physically attached in one place--eg, a "system"-type dslam--that would be able to switch the customer's service, e.g., from adsl to hdsl to something else, by software rather than physical connection. The "dslam" (in quotes because it is doing more than simply multiplexing dsl) would also route to non-dsl data connections. That seems to be the issue that Pairgain's Avidia system is addressing. Is this correct, and are there other products out there doing something similar? Finally, to get out of the CO there are several lines running. One is the voice line; this is supplied statistically--there are fewer potential lines running out of the CO than run into it, because not everyone will be on the phone at the same time (and when this is full we sometimes get a strange busy signal). A second is a T1 or T3 or OC3 type data line, depending on the size of the CO, or capacity needed. This similarly is provisioned statistically. Sometimes we get better throughput than at other times. For me a slow time seems to be when some local companies are submitting their end-of-day work at 5:00 to head office, so I can get a modem assigned in the CO to my little 28.8 connection, but on the back side of the connection the road is clogged by the other traffic. The interesting product in this scenario, to me, would be the one that would allow software-directed service changes without requiring physical wire changes. But, do I have the layout correct? And are there other significant products I am missing in the CO? Any corrections to the above would be gratefully accepted. Best regards, JS