[time-nuts] unknown Motorola GPSDO

[Stanley Reynolds]

Yes, with the jumpers in place it may not matter if the program is running or not, place the jumpers on the GPSDO RS232 connector and you may even be able to disconnect the PC end of the cable.
 
The other posibilty is some type of watchdog timer that is looking for data from the PC if that is the case a jumper between pins 2 and 3 may help. But that would be someting I tried last.
 
Stanley 
 
PC---GPSDO
1 ------ 1 shield
2 ------ 2 Data
3 ------ 3 Data
7 ------ 7 GND
 
4\
5/
 
 6\
 8+
20/
 
Note pin numbers are 25 pin numbers 9 pin numbers are:
 
9
pin #
25
pin#
Acronym
Full name
Direction
Mean
3 2 TxD Transmit Data —» Transmits bytes out of PC 
2 3 RxD Receive Data «— Receives bytes into PC 
7 4 RTS Request To Send —» RTS/CTS flow control 
8 5 CTS Clear To Send «— RTS/CTS flow control 
6 6 DSR Data Set Ready  «— I'm ready to communicate 
4 20 DTR Data Terminal Ready —» I'm ready to communicate 
1 8 DCD Data Carrier Detect «— Modem connected to another 
9 22 RI Ring Indicator «— Telephone line ringing 
5 7 SG Signal Ground     
 


----- Original Message ----
From: Bill Janssen <billj at ieee.org>
To: Stanley Reynolds <stanley_reynolds at yahoo.com>
Sent: Monday, September 22, 2008 3:08:46 PM
Subject: Re: [time-nuts] unknown Motorola GPSDO

Stanley Reynolds wrote: 
Bill,
 
Try a jumpers on the RS232 cable 4 to 5 and 6,8,20 together. If you have a RS232 break out box you could put it between the PC and GPSDO to see which levels change when the program is running.
 
Stanley N4IQT
  Thanks but I already have communications between the GPS and the PC. Do you mean that the 
GPS will think the PC program is running when I disconnect the PC? Haven't tried that.

Bill K7NOM


----- Original Message ----
From: Bill Janssen <billj at ieee.org>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Sent: Sunday, September 21, 2008 8:48:45 PM
Subject: [time-nuts] unknown Motorola GPSDO

A friend of mine has two Motorola GPSDO's that I have little  experience
with.
I was checking one of the units using TAC32 and I discovered that it
would lock the 5 MHz
to GPS ( as compared with my Z3801) when the PC software was running
When I stopped
the TAC32 it would lose lock.

Anyone have a clue what this thing needs to stay locked..

The circuit board has a date of 1992 and it has a label that has
TRN7793818  LA081WN.
On the back it has connectors for;
48 Volt power
Redundancy Control
Remote GPS (10 pin)
RS232 DCE
1 PPS out
5 MHz out.
And an On Line LED

Amy place I can get more information?

Bill K7NOM


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