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

Ulrich Bangert df6jb at ulrich-bangert.de
Sun May 23 10:29:52 UTC 2010


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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