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

Jeff Hook jeffhook at comcast.net
Sun May 23 17:42:45 UTC 2010


Bob
My 3805 cables look like this

DB9      DB25
2              2
3              3
5              7
(Null Modem)

Jeff

----- Original Message ----- 
From: "Robert Benward" <rbenward at verizon.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Sunday, May 23, 2010 10:30 AM
Subject: Re: [time-nuts] Z3805 utility, Was: AW: (no subject)


> 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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