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Re: cost of residential ISDN (fwd)
- To: firstname.lastname@example.org
- Subject: Re: cost of residential ISDN (fwd)
- From: James Love <email@example.com>
- Date: Tue, 16 Jan 1996 14:53:18 -0500 (EST)
---------- Forwarded message ----------
Date: Mon, 15 Jan 1996 18:10:43 -0600
From: Marty Tennant <firstname.lastname@example.org>
To: Multiple recipients of list <email@example.com>
Subject: Re: cost of residential ISDN
I'm no central office salesman or engineer, but I used to sell PBX's for
Southern Bell and AT&T. I think most central offices sold these days that
support ISDN are essentially or fully non-blocking, which means the
switching matrix and communications bus can provide as many dialup
connections, within the switch, as the number of lines supported.
So that means that, within a 10,000 subscriber line capacity central office,
5,000 folks could be talking to 5,000 other folks on the same switch at the
same time. No increase in costs would result (maybe more power consumption)
and the capacity would be there from the time of installation.
Does that mean that 4,000 folks could be talking to 4,000 other folks, and
the remaining 2,000 subscribers calling out over interoffice trunks? That
would depend on the configuration of the switch and the number of
interoffice and IXC carrier circuits provided.
So that leaves you your variable costs, which are the interoffice, or trunk
side connections. These are mainly made over existing fiber optic links
with incredible capacity and lowering costs, so that doesn't seem like such
a big deal either.
Seems to me that the real additional costs come from having to install
special line cards to make the ISDN link work on the CO end. This card
would replace the analog interface card normally provided to a POTS
subscriber. Maybe the $4 a month increase you mention would be more than
enough to cover the cost of the new line card.
Perhaps an AT&T or RBOC techie could confirm this for us?
Marty in MB