[1000mp] Computer Interface

[Jim Hill]

I had the same trouble trying to get on PSK-31 using the packet plug 
for doing the keying (PTT).  I tried using an isolator with higher 
current rating.  What worked was to use the PTT jack (the RCA jack).
73, Jim, K6UUW

On Aug 30, 2005, at 11:33 AM, Bob Warren wrote:

> Hi Doug
> Sounds as if your optoisolators can not 'sink' the current on the PTT 
> line. Select another isolator with a higher Icmax.
> Bob W2ZXQ
> ----- Original Message ----- From: "Doug Rehman" <k4ddr at earthlink.net>
> To: "'All about Yaesu 1000mp'" <1000mp at mailman.qth.net>
> Sent: Sunday, August 28, 2005 10:45 PM
> Subject: [1000mp] Computer Interface
>
>
>> I just finished building an interface for my Field for both CW and 
>> digital
>> modes. I used the circuit found at 
>> http://www.qsl.net/wm2u/interface.html
>> for both the CW key and the PTT. The CW key works perfectly from the
>> computer, but I am having a problem with the PTT line. The PTT line is
>> connected to Pin 3 of the "Packet" connector.
>>
>> When keyed by the computer, the PTT voltage drops from 13.4 volts to 
>> about
>> 2.7 volts- not enough to key the radio. If I parallel 50 ohms across 
>> the
>> opto isolator's output, it works like it is supposed to (the standby 
>> voltage
>> on the PTT line drops to about .7 volts, but the radio isn't keyed 
>> until the
>> computer keys it).
>>
>> I've tried to use the CW key output for PTT, but it does the same 
>> thing so I
>> don't think it's a wiring or component issue.
>>
>> I've also checked the ground connection- no problem (.1mV difference
>> according to my DVM).
>>
>> It won't key the radio from the  PTT connector on the back either.
>>
>> I've used this exact same circuit before on a Kenwood TS-430S and 
>> TS-2000
>> without any problems.
>>
>> Any ideas? Anybody experienced this before?
>>
>> Hanks,
>> Doug
>> K4DDR
>>
>>
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