Re: Twisted Pair---Balun---Twinax

Mark

The twinax devices use to come with manuals of twinax information & IBM used
to have overall twinax info manuals on hooking up the hardware, including
instructions on how to assemble our own connectors & verify they working
right.  Examples:
Operator's Guide (e.g. GA21-9409)
Setup Guide (e.g. GA 21-94508)
Maintenance Guide (e.g. SY31-0661)
I looked for ours without success, thinking I could help you by quoting from
IBM manual with particulars you needed.

You'll need a remote controller such as what Perle has to offer.
1-800-GO-Perle   They've got models to handle both twinax & PC at same time
so flexibility exists to switch as the time comes.

Many of the 3rd party places in the business of buy/selling twinax
peripherals could offer by fax relevant reprints of info about the
capabilities of the devices they dealing in, including reprints of info no
longer available from IBM documentation.  Check ads in News/400 magazine for
who still in the business.  There were also a few 3rd party places in the
twinax business & for some inexplicable reason they never advertised much in
the 400 media ... cables, baluns, splices, cable city management, factoids
etc. so their catalogs might share information about this technology which
has fallen out of today's IBM documentation.

South Hills Data Comm 800-245-6215 in Pittsburgh PA fax # 1-412-921-2254 was
best @ www.shillsdata.com with great illustrations in their catalog
www.blackbox.com 800-552-6816 in Pittsburgh PA fax # for calls from outside
USA 412-746-0746 (I wondering if "nu-z" means New Zealand down under) was
second best but I think they merged & I not remember which ended up on top
I still have one old manual from each of them (several years old) & could
look up other factoids, for example, quoting from Solution 13 of
Midrange/Other in an ancient South Hills Data Comm catalog
"Cable runs of up to 5,000 feet, without the use of any type of signal
booster, are possible using twinax cable."

At one time I understood maximum safe splices on a twinax line was 11,
including the daisy chain connections, with number to be reduced when
different kinds of devices on same line ... for example needing pigtails,
actually going through the daisy chain, brand name emulators inconsistency on
same line, swtiching between connection method & back again.

Twisted pair apparently beats twinax for signal quality when lots of
interference like factory machines & our remote site is next door to airport
radar, because the technique for blocking interference is different.  I have
also found the best way for the gremlins to cause interference is that when
there is improper termination after rearranging what is connected on a daisy
chain line ... an extra cable up in the roof without a device on the end, can
do wonders for the weird symptoms on a line ... I call this a gremlin
antenna.  IBM cabling system combines best features of both twisted pair and
twinax, into something better than either.

I once worked at a place which strung its own "like ma bell" cable to connect
two rural buildings, crossing property we did not own, which invariably went
down (dead) in a weather front, which is better than becoming an antenna (for
lightning).  As much as we rail against our local ma bell for similar
performance (dead in storm), I also know of several instances of lightning
getting into a computer room via phone line (the closest any place I ever
worked was lightning zapping an IBM modem fuse ... I figure the modems of
today are so puny that lightning would go right through them to wipe the
computer itself), so I guess we have lesser of several evils.

We used to be dedicated phone line, but we were sold on VPN which
concurrently handles communications between our offices for AS/400, PC
intranet, fax machines, voice, and remote city connects to manin city as
local dial.  I am not the expert on this stuff.

MacWheel99@aol.com (Alister Wm Macintyre) (Al Mac)
BPCS 405 CD Manager / Programmer @ Global Wire Technologies Incorporated
http://www.globalwiretechnologies.com = new name same quality wire
engineering company: fax # 812-424-6838