[Premium-Rx] LOGSA increased security?

Tue Jul 11 13:19:43 EDT 2006

The USM-181 manual can be viewed at http://www.tpub.com/content/telecomtest/TM-11-6625-602-12/index.htm

Be however prepared that this instrument is not exactly "rocket science"...

The HP353A "patch panel" is basically an adjustable attenuator with switchable input and output matching transformers.

They enable the "test set" to operate at the 3 most common balanced line impedances; 135 ohms used in carrier multiplex systems, 600 ohms which is the "general purpose" Telco/PTT line impedance and 900 ohms which was sometimes encountered in some PBX systems and some Pupin-coil loaded "phantom" and "super-phantom" systems. The "input" selection also has a "BRG" (= bridging) or high-impedance option which can be used for measuring "across" telephone lines. (Beware of DC on some lines; it can destroy the input transformer).

I recall that I have used the commercial equivalent of the USM-181 a few times "ages" ago, but also that it was considered a "pain in the***" to use compared to the "Siemens Pegelkoffer" that was the mainstay of analog Telco/PTT line maintenance in Europe 25 years ago. The Pegelkoffer contained most of the functions of the USM-181 in two easily carried and very intuitive instruments.

73/

Karl-Arne
SM0AOM

----- Original Message ----- 
From: "Barry Hauser" <barry at hausernet.com>
To: <premium-rx at ml.skirrow.org>; "Blair Batty" <Blair at Amtelecom.net>
Sent: Tuesday, July 11, 2006 12:13 AM
Subject: Re: [Premium-Rx] LOGSA increased security?

> Hi Blair & group
> 
> I don't know if LOGSA has changed anything, though a few vintage manuals I 
> used to find there are missing altogether -- at least it looks that way.
> 
> However, it is still the case that some manuals can be opened and/or 
> downloaded without an ID and password and others cannot -- are still 
> technically restricted.
> 
> As before, there is often no rhyme or reason as to which are publicly 
> accessible and which are not.  I've found that detailed maintenance manuals 
> were "allowed" while the simple operator's manual for the same gear was 
> still restricted -- basically shows where the on-off switch is.  Some 
> manuals for long-obsolete equipment is restricted, while some manuals for 
> things like parts of the certain currently-in-use missle systems are 
> available without ID.
> 
> If you "hover" over the manual link you will see an assortment of 
> folders/directories in them.  Only those in the "A" subfolders can be 
> downloaded without an ID/password.  "B","C","D", "BNF","DNF", etc.... or 
> anything but "A" require login.
> 
> That "USM-181" manual is in a "D" directory.   However, the calibration 
> manual TB 9-6625-2127-35 is an "A" file.  Also the TM 11-6625-2779-14&P is 
> available as is the TM 9-6625-1941-34P which I found by searching just 
> "353A".  It refers to it as a patch panel.  Don't know if they're any help. 
> You sometimes have to search several ways.
> 
> Of course, being a Canadian national, there is an initiation -- on the honor 
> system.  You have to sing the Star Spangled Banner backwards to the tune of 
> O' Canada three times in a row with no mistakes, and then there's the secret 
> handshake, which looks like this [deleted].  ;-)
> 
> BTW -- be wary of those manuals that were published 
> pre-Internet/pre-ARPANET.  Although in acrobat format,  they were scanned 
> and OCR-ed from hard copy and were not totally cleaned up for OCR errors.
> 
> Barry
> 
> 
> ----- Original Message ----- 
> From: Blair Batty
> To: premium-rx at ml.skirrow.org
> Sent: Monday, July 10, 2006 1:45 PM
> Subject: [Premium-Rx] LOGSA increased security?
> 
> 
> The HP-353A is part of the HP 3550A Carrier Test Set, aka AN/USM-181 
> Telephone Test Set.  There are several manuals, as I recall they are 
> available on LOGSA.
> 
> Craig
> 
> Thanks Craig. A quick search of LOGSA on "AN/USM-181"
> found the pdf. Unfortunately LOGSA demanded a password before
> it would give it to me. I used to be able to download from LOGSA,
> I guess they increased security.
> 
> If anyone has access and would forward it to me, I'd be very grateful.
>   <Blair at Amtelecom.net>
> 
> Sincerely
> Blair VE3CZY Canada
> 
> 
> Law of Logical Argument:
> Anything is possible if you don't know what you're talking about.
> 
> 
> 
> 
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