-----Ursprungliche Nachricht-----
Von: time-nuts-boun...@febo.com
[mailto:time-nuts-boun...@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" <li...@rtty.us>
To: "Discussion of precise time and frequency measurement"
<time-nuts@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
<did...@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.griffi...@xtra.co.nz>
>>> Date: Sun, 23 May 2010 10:39:21
>>> To: Discussion of precise time and frequency
>>> measurement<time-nuts@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-boun...@febo.com
>>>> [mailto:time-nuts-boun...@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-boun...@febo.com
>>>> [mailto:time-nuts-boun...@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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