Why not just use one MON4B,
Put the contacts across one analog ext port
Put a resistor in line with the relay (i don't remember what value is best
right now) so you don't load down the circuit with a dead short.
Program that ext to grab only the one line.
Put call blockers thingy on the the fax machine (or other device). You know
the zener diode things that block a phone from breaking in if the line is
already off hook. This way if the ksu is using the line, the fax will get
dead air, if the fax is on the line first, then the relay will make the ksu
also jump on the line and block others from accessing it. The ksu on the co
at the same time as the fax should not make a problem, if it did you could
also put a call-blocker on the ksu I suppose.
Charles
----- Original Message -----
From: "Mike Magnus" <[EMAIL PROTECTED]>
To: "KXT Mailing list" <kxt@kxthelp.com>
Sent: Friday, April 22, 2005 11:29 AM
Subject: Re: KX-T: Use analog pair without phone set?
> (ME = David Lesher)
>
>> {lift CO from trunk port; put busy there..}
>>
>> Mike:
>>
>> It is the KSU and not the user that needs to know
>> the line is busy. I can't think of any way to tell the
>> KSU that a CO is busy other than to pick up a station
>> associated directly with that CO.
>
>> Charles:
>>
>> That device from Mike Sandman does work. www.sandman.com
>> You have to be a bit clever with wiring it up, but it
>> will do what you described.
>>
>>
>> Me:
>>
>> What device from Sandman?
>
> I was thinking of something like the MON4B loop sensing relay on this
> page.
>
> http://www.sandman.com/wizard.html
>
> However, I see it only has one form C contact, which isn't enough to do a
> proper job. To do it right you need two form B or C
> contacts (N.C.) to break T&R to the KSU when the direct device goes OH.
> You also need one form A or C (N.O.) to pickup an extension
> in order to busy out the CO line from the KSU's point of view. (Not sure
> how well the KSU would tolerate a direct short on an analog
> station port, so a resistance in series might be in order.)
>
> To do this with the Sandman's relays, you'd need the MON4B and two MON4Es
> (or some other suitable general purpose relay with enough
> contacts). You'd also need an appropriate power supply for the AUX
> relay(s). Gets pretty complicated and expensive.
>
> This 'simple' solution has two flaws I can think of... You can still get
> into a 'glare' situation where both devices (e.g., modem
> and KSU) attempt to seize the line simultaneously. Second, the direct
> device has no way of knowing that the KSU has seized the line
> and will butt in on the connection if asked to, cutting off the KSU
> caller. A more complete solution would require yet another loop
> relay to cut off the direct device when the KSU seizes the line.
>
> I had worked this out at one point, when I was using dialup and found that
> the modem would not connect at high speeds through my
> KX-TD816. However, I switched to DSL and never actually build the device.
>
> -Mike
>
>
>
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