[time-nuts] Z3805 utility, Was: AW: (no subject)

Robert Benward rbenward at verizon.net
Sun May 23 15:30:26 UTC 2010


Ulrich,
On pin 2 of the DB9, I get -0.5V, and on pin 3 (TX) I get +2.0V.  Doesn't sound good.  I have a 3805 that has only the 
bottom DB25 connector.  The person who sold it to me made a 3 wire cable, DB25 to DB9, with pins 2&3 reversed and pin 7 
grounded.

Bob


----- Original Message ----- 
From: "Ulrich Bangert" <df6jb at ulrich-bangert.de>
To: "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
Sent: Sunday, May 23, 2010 6:29 AM
Subject: Re: [time-nuts] Z3805 utility, Was: AW: (no subject)


> Bob,
>
> even without a computer connected the beast should do SOMETHING. In
> conjunction with a pc and a running communication it is easier to judge WHAT
> it currently does.
>
> To establish communication first find out what pinning the RS232 connector
> has: with the negative cable (black) of a voltmeter connected to Pin 7 of
> the RS232 connector check pins 2 & 3 with the positive cable (red) for the
> presence of a NEGATIVE voltage of a few Volts. If you can measure a negative
> voltage on one of the pins, you have successfully identified the Z3805's
> TRANSMIT pin. The other pin of 2/3 is the receive pin.
>
> Then solder a cable in this way
>
> Z3805 Transmit pin  -> Pin 2 of pc RS232 port (9 pole D-Sub assumed)
> Z3805 Receive pin   -> Pin 3 of pc RS232 port (9 pole D-Sub assumed)
> Z3805 Ground (7)    -> Pin 5 of pc RS232 port (9 pole D-Sub assumed)
>
> Should you have a 25 pin connector for RS232 at your pc then the cable is
>
> Z3805 Transmit pin  -> Pin 3 of pc RS232 port
> Z3805 Receive pin   -> Pin 2 of pc RS232 port
> Z3805 Ground (7)    -> Pin 7 of pc RS232 port
>
> No other connection is needed. With a cable like this start Z38XX and check
> that you that you choose the correct Com-Port for communication in the
> Parameters window. And yes, I know, being an owner of a Z3805 I should know
> exactly but I don't remember the day that I made the cable and I currently
> cannot access the back of my Z3805.
>
> Best regards
> Ulrich Bangert
>
>> -----Ursprungliche Nachricht-----
>> Von: time-nuts-bounces at febo.com
>> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Robert Benward
>> Gesendet: Sonntag, 23. Mai 2010 05:31
>> An: Discussion of precise time and frequency measurement
>> Betreff: Re: [time-nuts] Z3805 utility, Was: AW: (no subject)
>>
>>
>> Thank you all for these inputs!
>>
>> Most importantly, the big question is:  Regardless of RS-232
>> or 422, will the unit do ANYTHING without communications?
>> Do I need a computer to get anything beyond the "power" led?
>>
>> I bought this at the Dayton convention ham flea market, and
>> the guy told me it was already modified for RS-232.  The
>> board inside says RS-422 near the connector.  Without the
>> other LEDs blinking, I'm worried I bought a dead unit.  I had
>> a GPS antenna on it, but it never locked on.  Do I need a
>> computer to enable this thing?
>>
>> Thanks,
>> Bob
>>
>> ----- Original Message ----- 
>> From: "Bob Camp" <lists at rtty.us>
>> To: "Discussion of precise time and frequency measurement"
>> <time-nuts at febo.com>
>> Sent: Saturday, May 22, 2010 10:54 PM
>> Subject: Re: [time-nuts] Z3805 utility, Was: AW: (no subject)
>>
>>
>> > Hi
>> >
>> > In this case the RS relates to Radio Shack ......
>> >
>> > Not a lot of standardization in the RS-232 world. Take a
>> look at the
>> > slew rate limiting requirements in the original
>> > document ...
>> >
>> > Bob
>> >
>> > On May 22, 2010, at 9:47 PM, Robert Darlington wrote:
>> >
>> >> Was there ever a standard?  I always thought the "RS" stood for
>> >> Recommended Standard, as in "you *should* do the following" as
>> >> compared to "you shall do the following"  I've seen
>> inverted TTL talk
>> >> to the RS232 port on laptops and I even sometimes use the max233's
>> >> (+/- 10 volts instead of 12), but always use the full max232 with
>> >> external charge pumps when it's a gadget that needs to
>> work everytime
>> >> with systems from multiple countries.
>> >>
>> >> -Bob
>> >>
>> >> On Sat, May 22, 2010 at 7:21 PM, Didier Juges
>> <didier at cox.net> wrote:
>> >>> Bruce,
>> >>>
>> >>> Thanks for the additional information.
>> >>>
>> >>> +/- 14V is quite unusually low in my experience. I typically use
>> >>> +Maxim parts such as the MAX220 series, which is
>> >>> specified at +/-25V for no damage on the inputs (some
>> parts in that
>> >>> series go to +/-30V).
>> >>>
>> >>> The bottom line is that as I pointed out earlier, there
>> is no such
>> >>> thing as an RS-232 standard any more.
>> >>>
>> >>> Didier
>> >>>
>> >>> ------------------------ Sent from my BlackBerry Wireless thingy
>> >>> while I do other things...
>> >>>
>> >>> -----Original Message-----
>> >>> From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
>> >>> Date: Sun, 23 May 2010 10:39:21
>> >>> To: Discussion of precise time and frequency
>> >>> measurement<time-nuts at febo.com>
>> >>> Subject: Re: [time-nuts] Z3805 utility, Was: AW:  (no subject)
>> >>>
>> >>> Didier Juges wrote:
>> >>>> Bill, I think you got it backwards. +/- 12V is typical
>> for RS-232,
>> >>>> 0/+5V is for RS-422 and RS-485.
>> >>>>
>> >>>> No RS-232 receiver should be damaged with +/- 12V or
>> even +/- 15V
>> >>>> because that is their normal operating voltage.
>> >>>>
>> >>>> Also, RS-422 and RS-485 have something like 25V common mode
>> >>>> tolerance (not sure what the actual spec is there,) so that the
>> >>>> RS-422 and RS-485 receivers should not be damaged by 15V either.
>> >>>> The RS-422 drivers are pretty low impedance, while the RS-232
>> >>>> drivers are current limited, so I don't think that connecting an
>> >>>> RS-232 driver into an RS-422 driver will damage either.
>> >>>>
>> >>> Picking one RS485 receiver (ADM1485) at random the
>> receiver absolute
>> >>> maximum (no damage) input range is -14V to +14V. The
>> RS485 receiver
>> >>> operating common mode range is -7V to +12V. RS422
>> receivers have an
>> >>> input operating range of -7V to +7V. The no damage RS422 receiver
>> >>> input ratings may be higher.
>> >>>> However, most recent (<10 years?) RS-232 receivers will
>> work with a
>> >>>> 0/+3V or 0/+5V input, conveniently having a threshold a
>> few 10's or
>> >>>> 100's of mV above ground, even though the original RS-232 spec
>> >>>> required receivers that work with as low as +/- 3V, and drivers
>> >>>> that deliver +/- 9V minimum. Many commercial systems use +/- 5V
>> >>>> drivers for RS-232 (B&B Electronics sells a lot of
>> converters with
>> >>>> these voltages). This is a deliciously sloppy spec that
>> nobody has
>> >>>> met in the last 25 years probably, yet works most of the time.
>> >>>>
>> >>>> The one thing to avoid is to short an RS-422 (or RS-485)
>> driver to
>> >>>> ground, as that can actually cause damage, maybe not every time,
>> >>>> but definitely not recommended. These have relatively
>> high current
>> >>>> output capability to drive long lines.
>> >>>>
>> >>>> Didier KO4BB
>> >>>>
>> >>>>
>> >>>>
>> >>> Bruce
>> >>>> -----Original Message-----
>> >>>> From: time-nuts-bounces at febo.com
>> >>>> [mailto:time-nuts-bounces at febo.com] On Behalf Of Bill Hawkins
>> >>>> Sent: Saturday, May 22, 2010 3:09 PM
>> >>>> To: 'Discussion of precise time and frequency measurement'
>> >>>> Subject: Re: [time-nuts] Z3805 utility, Was: AW: (no subject)
>> >>>>
>> >>>> When all else fails, get out the voltmeter.
>> >>>>
>> >>>> Do you have power to the antenna? Is it the right
>> voltage? All the
>> >>>> way to the antenna?
>> >>>>
>> >>>> What volts are on pins 2 or 3 relative to pin 7 in the comm
>> >>>> connector?
>> >>>>
>> >>>> If you see 12 volts, that's RS-422. You may have burned out your
>> >>>> computer's serial port.
>> >>>>
>> >>>> If you see less than 5 volts, that's RS-232 and all
>> should be well,
>> >>>> unless you see zero volts.
>> >>>>
>> >>>> I may have the RS-xxx volts somewhat off because my memory isn't
>> >>>> what it used to be.
>> >>>>
>> >>>> The guy you bought it from should be able to help with
>> comm basics.
>> >>>>
>> >>>> Bill Hawkins
>> >>>>
>> >>>>
>> >>>> -----Original Message-----
>> >>>> From: time-nuts-bounces at febo.com
>> >>>> [mailto:time-nuts-bounces at febo.com] On Behalf Of Robert Benward
>> >>>> Sent: Saturday, May 22, 2010 2:08 PM
>> >>>> To: Discussion of precise time and frequency measurement
>> >>>> Subject: Re: [time-nuts] Z3805 utility, Was: AW: (no subject)
>> >>>>
>> >>>> Hi All,
>> >>>> I hooked everything up and I still get nothing.  I can't seem to
>> >>>> establish communications  with the Z3805.  I tried a
>> null modem as
>> >>>> well, in case the cable (supplied) was wired with the wrong
>> >>>> connector gender.  I see a green blinking light inside,
>> it he left
>> >>>> rear corner of the box.  Everything is warm, but nothing
>> else.  Any
>> >>>> ideas?
>> >>>>
>> >>>> Bob
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>> _______________________________________________
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>> >>>>
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>> >>>>
>> >>>
>> >>>
>> >>>
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