Bob - I have a Symmetricom/HP Z3805. When I first got it I powered it up in the North end if my house, where car GPS's can't lock, left it on for a day or more, and it locked. No computer involved. The antenna is a MA/COM mag mount from 1997. I bought the unit from fluke.l on ebay from China.
John Allen K1AE -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Robert Benward Sent: Saturday, May 22, 2010 11:31 PM To: Discussion of precise time and frequency measurement Subject: 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" <[email protected]> To: "Discussion of precise time and frequency measurement" <[email protected]> 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 <[email protected]> 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 <[email protected]> >>> Date: Sun, 23 May 2010 10:39:21 >>> To: Discussion of precise time and frequency measurement<[email protected]> >>> 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: [email protected] [mailto:[email protected]] 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: [email protected] [mailto:[email protected]] 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 >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- [email protected] >>>> To unsubscribe, go to >>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- [email protected] >>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>>> and follow the instructions there. >>>> >>>> >>> >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
