TELECOM@Usc-Eclb (07/29/82)
TELECOM AM Digest Thursday, 29 July 1982 Volume 2 : Issue 94
Today's Topics:
Phone Service Outage - Some Not Affected?
Whats NPANXX - More Detailed Expansion Notes
Survey - Portable Telephone Sought
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Date: 27 Jul 82 21:24:55 EDT (Tue)
From: Steve Bellovin <smb.unc@UDel-Relay>
Subject: phone service outage
According to the local paper, phone service here was "out of order"
for about 75 minutes today. I was logged on to our machine via a
dial-up port during that time; I experienced no interruption of
service. How is that arranged? (John Covert mentioned in a previous
note that the University at least is serviced by a No. 1 ESS CO
CENTREX; I assume that's what serves the town as well. I was calling
a University number from a non-University phone.) I was no longer
logged on when service was restored, so I don't know if the
restoration process ("they then begin to load the system recovery
tape, and get an arrangement of the system configuration tape") would
have dropped my line. My speed-dialing codes are still correct, but I
haven't changed any lately; even an old backup tape would have them
right. Comments?
--Steve
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Date: 27 Jul 1982 22:25:45-PDT
From: ihnss!houxn!govern at Berkeley
Explanation of NPA-NXX:
NPA=Numbering Plan Area, thus = area code
NXX: N is a digit from 2....9
X is any digit
For quite a while, the North American Numbering Plan used NPAs of the
form N [01] X, and central office codes of the form NNX. This permits
simple translations to distinguish between 7 and 10 digit numbers,
allowing enough digits to be collected (on stored-program-control
switches) or forwarded (on step-by-step). However, there are only 640
NNXs, vs. 800 NXXs, and it is often less traumatic to convert to NXX
central office codes instead of splitting an area code when the NNXs
run out. (This requires another mechanism for distinguishing between
7 and 10 digit calls: either timing after the 7th digit
(non-standard), or requiring all 10-digit calls to use a "1" prefix (
the approved method, and future standard )). The 1+10 digits is a
mild annoyance for people who aren't used to it, and there are some
difficulties in areas with step-by-step, where you dial 1 for a
7-digit toll call. According to "Notes on the Network", the
recommended solution for 7-digit toll calls from step-by-step
switches, when NXXs are used, is 1-NPA-NXX-XXXX, where NPA is your own
area code. 1-NXX-XXXX with time-out is not recommended, but it's
probably done in some places.
The tining mechanism is normally a 4-second wait after the 7th
digit, and is only needed when you dial a code that is used as a
central office code as well as an NPA.
The phone company is trying to get everyone to dial 1+ for
10-digit toll calls by 1990, whether you need it or not. Area codes
of the form N[01]X will run out around the year 2000 (+-5 or so), and
area codes of the form NN0 will be introduced after that.
Bill Stewart, BTL West Long Branch, New Jersey
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Date: 28 Jul 1982 1115-PDT
From: Jon Solomon <JSol at USC-ECLC>
Subject: Portable Telephone Wanted:
I am looking for a portable telephone, which must have the following
features:
1 - a range of at least 2 miles (low wattage units with extenders are
plausable)
2 - some form of code number. Preferably something which logs failures
so I know when I am being hacked, but not necessary.
3 - touch tone preferred but not required.
4 - FCC approved for both transmissions and interconnection to Telephone
Network.
I want 2 of these beasts. If you know of any portable telephones which
are on the market today which can be of help to me, please let me know.
Let's assume I don't get any responses to this. I have an ad for
a "ROVA/PRO" Cordless Extension Phone, 3 models, one with a 5
mile radius, one with a 15 mile radius, and one with a 25 mile radius.
It is NOT FCC approved for use in USA (displayed in fine print on the
ad itself).
I called the number on the Ad, and the salesman told me that the 25
mile radius one's mobile transmits on the 49 Megahertz band (typical
band for portable phones) at 25 Watts, and the base transmits on the 70
MHZ band at 30 Watts. I did not ask if the unit had an FCC registration
number for telephone interconnect. He claims that the 70 MHZ band is
the loser, and is why the FCC won't approve of its use.
What would I have to do to make this unit legal? Is it worth spending
the $800 bucks on it to get 99% of the workings of a phone, and perhaps
change one set of crystals (and adjust the transmitter accordingly)?
Could I have a Radio Tech. do this and get approval from the FCC?
Could I get an FCC registration number if there isn't one? Should I
give up and wait 2 years for Cellular?
Cheers,
--JSol
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End of TELECOM Digest
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