[comp.dcom.telecom] Query: Cordless Portable Hand-free Telephone Set

Arthur_Axelrod.WBST128@xerox.com (03/02/90)

Does anyone know a source for a cordless portable hand-free telephone
set?  That is, a cordless portable telephone that has a
headset-microphone rig rather than the usual handheld unit, and with a
base unit that plugs into a standard POTS line, rather than cellular
or anything exotic.

Thanks.

Art Axelrod
Xerox Webster Research Center
Axelrod.WBST128@Xerox.COM

tad@ssc.UUCP (Tad Cook) (03/05/90)

Art Axelrod asked if there is a cordless portable headset type phone
that plugs into a regular POTS line.

I am using one at work.  It was made by Plantronics, then
discontinued.  I bought it from the DAK catalog.  It was cheap!

It works on the regular 46/49 MHz cordless phone frequencies.  My boss
and I got a pair on different channels, and hooked them up in parallel
with the phones on our PBX extensions.  The PBX is compatible with
regular POTS phones.

One thing to watch out for...computer RFI.  You may have to get some
ferrite beads and conductive paint to tone down the noise from PCs and
terminals in the area.

We find these very handy for roaming around the plant, so we can still
answer calls quickly.  It is very handy if I have to run down the hall
to look up something in a file.  I can keep talking to the customer
all the way.

Another handy use is just as a remote ringer.  Sometimes the RFI is
bad enough in the office that I can't have a really clear call when I
am a long distance away, but the ringer still works.  So on our ROLM
PBX, I just walk over to any extension and dial the call pickup code,
followed by my extension number.

I confess....being a ham I could not resist modifying mine.  The
antenna is typical for a cordless phone....short.  A quarter wave
groundplane seemed like a good idea.  A quarter wavelength antenna in
the 46/49 MHz region is about 5 feet (quarter wave at 46.8 MHz).  I
opened up the housing of the base unit, disconnected the external
antenna, and ran a five foot wire out that I taped vertically to the
wall (used the same color wire that matched the paint!).  Then I
located the ground plane on the circuit board, and attached an
external ground radial system.  These are also 1/4 wave (5 feet) long.

The base unit is on top of a metal file cabinet, next to the wall.  I
ran two radials, one in each direction, horizontally along the wall.
Then two more ran out at angles across the file cabinet, with the ends
taped down the opposite corners.  This gives good ground coupling to
the radial system, and makes for an efficient low-angle radiator.  It
also violates the FCC type acceptance.

The range on this is incredibly good.  The downside is that when the
secretary in the next office turns on her computer, which is located
directly on the other side of the wall from my base unit, it gets VERY
noisy, unless I am withing 60 feet or so.  The first day I had this
arrangement, I took a walk way out into the woods, lay down in the
sun, and took a few customer calls!

Remember that cordless phone calls are NOT private!

DAK still had the cordless LiteSet in their latest catalog.

Have fun!


Tad
tad@ssc.UUCP
 ...uw-beaver!amc-gw!ssc!tad

jeh@simpact.com (03/06/90)

In article <4737@accuvax.nwu.edu>, tad@ssc.UUCP (Tad Cook) writes:

> (complimentary things about the Plantronics cordless headset phone
> sold by DAK)

I have one too and I agree with everything Tad said.  I did have
trouble at first keeping the ear unit in my ear; the weight of the
cord tended to pull it out, and furthermore tended to rotate the mic
"boom" so it pointed too far downward for good voice pickup.  I solved
that by simply looping the cord over the top and back of the ear unit
instead of just letting it hang; now the weight of the cord tends to
rotate the boom up, where it belongs.

Just one complaint: The hookswitch ("on/off" button) on the remote
unit does not operate fast enough to allow a "hookflash", so I can't
access most of our PBX system's fancy features.

But for handling those long customer calls that involve lots of
terminal use, reference to manuals, etc., it's great!

And Tad is right about using it as a "remote ringer".  I haven't
modified the antenna on mine, and it can still punch through well over
100 feet worth of modern office interior space (many partitions built
with aluminum 2x4s, lots of tall metal desk and file cabinet units,
etc.) and ring the ringer on the remote *when I'm in the restroom
surrounded on three sides by double-layer metal partitions*.

Not bad at all, considering that DAK is selling these for $70 (less
than the cost of a conventional cordless phone, and less than the cost
of the same ear unit set up as a *wired* headset from Hello Direct!),
and that DAK has a 30-day no-questions-asked return-for-full-refund
policy.

	--- Jamie Hanrahan, Simpact Associates, San Diego CA

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