10base-T & POTS in same Cat-5 cable?

You have to build a DC interconnect.

Having grids synchronized over areas bigger than around 1200 km in diameter becomes unwieldy. You will have phase effects and frequecy wabbles migrating into the system.

The US understood this a little late in their design.

-- mrr

The US has several significant DC Interties. The first is the Pacific Intertie, bring hydro power from Washington State to LA. Another brings Canadian hydro down to the Twin Cities region...

I believe a third, along the Mississippi, joins the east & west grids.

three major 'grids' in the U.S.

eastern, western, and Southern Texas.

East-west boundary is (roughly) the east edge of New Mexico, Colorado, Wyoming, and Montana.

The "Southern Texas" grid is everything below a line from El Paso to roughly the north-west corner of Louisiana.

I think the east-west intertie is in the Oklahoma panhandle.

Source: POWER A Survey History of Electric Power Technology Since 1945 copyright 2000, IEEE History Center

on-line at:

Nope...THE one Texas grid (which is overseen by ERCOT) consists of MOST of Texas...See the map at:

......Entergy's TX area (which was originally GSU or Gulf States Utilities which covered SE TX from north west of Houston to Beaumont and into SW LA to Baton Rouge, LA) is not part of ERCOT but is a member of the Southwest Power Pool which IS part of the Eastern Interconnect. The system operators in Beaumont, TX were watching the frequency swing on the network when the big blackout in the NE happened (ironic, one of the plants in NY that dumped off line, Indian Point, is owned and operated by Entergy's Nuclear Division...but doesnt supply power to any of Entergy's service/distribution territory)...the part in SE TX on the map above that is greyed is Entergy's area...where Vernon parish in LA butts up to TX is the stopping point of Entergy's TX area...and then there is Swepco in the NE (part of Central and Southwest) as well as those in the panhandle who are not part of EROCT..but there is NO "southern" Texas grid....It is called THE Texas grid.. At last report, Entergy is splitting the Texas operations off from the LA side so the Texas area will then be somehow tied to ERCOT and will take part in the Texas deregulation

Chris Former Sr Telecom EGr/Tech, GSU-Entergy, TX 1984-1996

Funny part about this is that the original Edison system which was all DC was deemed inadequate because DC couldn't be transmitted any distance greater than locally, because transformers don't transform DC. So AC became the standard method of transport. But that was before the Pacific Intertie which used some kind of mercury arc tubes originally, then later solid state replacements. So the convenience of DC has returned. Things have come full circle.

We bought a big bldg last yr and refurbed it for our new campus, and moved in over Xmas. It sits next to some huge power pylons, transporting power from the Hoover dam over the desert to the L.A. metro area. There are three big lines each with its own set of pylons and some smaller lines, too. I've never heard them sputter or crackle at 60 Hz, so they may be running DC over them, too. But probably not, since it's more costly than AC, which just takes a big oil-filled transformer.