A computer can cope with this problem better or worse.
Changing the computer's hardware helps (confirmed, see [7]).
If this is not feasible, use a ferrite ring (see [8] for instance)
or two around the ends of the FHZ cable (semi-confirmed).
(or on other interference-inducing cables!)
Confirmed, AndiM: MANY issues with interference on FHZ1300PC,
which can be observed via drastically increased receiver LED activity
e.g. when a nearby (1m) PC is running - despite some countermeasures.<br>
Symptoms of trouble with interference:<br>
<ul>
<li>Almost no successful bi-di communication (almost never <code>ack:</code>s received when sending values),
(re-)pairing FHT80b units was pretty much impossible, too,
but many <code>can-rcv: 50</code> from several FHTs received while pairing was not successful
(hmm, perhaps this is a special ID for indication of pairing protocol issues,
since it's exactly half of FHTID 100??)</li>
<li>FS20 button reception does work directly after an <code>initFS20</code> or <code>rereadcfg</code> or other
reset command is executed, but as soon as the first other LED activity
(interference? FHT traffic?) happens, any FS20 reception whatsoever drops dead again.
And this specifically affects FS20 handling in FHZ1300PC,
since specifically <code>initFS20</code> does correct it (IIRC <code>initHMS</code> doesn't)
and (some parts of) FHT protocol reception still does work in the meantime.</li>
</ul>
Swapping the 1m USB cable with a 1.5m cable (but not overly long - this is said to be problematic as well!)
and adding a ferrite ring (currently at the FHZ1300PC-side cable end) did do wonders,
it completely eliminated all problems (although not sure yet which of these measures contributed by how much,
the increase of the distance from interference-causing parts or the ferrite ring).
Please also note that it is recommended to keep an FHT at least 1.5m from a FHZ, otherwise <ahref="http://www.razyboard.com/system/morethread-anmeldung-fht80b-funktioniert-nicht-haforum-53111-2713680-0.html">people experienced pairing problems</a>.
<H1> Misc. issues / hints </H1>
<ul>
<li>Make sure to have correct (and also unique, BTW) FHT codes, otherwise FHZ buffers may fill up due to trying to communicate with an unavailable FHT code
(<ahref="http://www.razyboard.com/system/morethread-kommunikation-fhz1000pc-zum-fht80b-haforum-53111-1988993-0.html">Kommunikation FHZ1000PC zum FHT80b</a>).</li>
<li>Diagnosing large-scale 868 MHz band distortion: <ahref="http://groups.google.com/group/fhem-users/browse_thread/thread/7e183113f6c95f2">empfänger empfangen nicht mer</a>.
<li>Still reception / interference issues? Try updating components to use a Superhet receiver (<ahref="http://www.ip-symcon.de/forum/f19/fs20-st-superhet-empfangsmodul-3580/index3.html#post29481">FS20-ST & Superhet Empfangsmodul</a>)</li>
