APPENDIX C
1.2.3 DC CODE (OPTION 01A)
0 to +5 volts into a 50Ω load.
1.2.4 CONTROL VIA THE RS-232 I/O PORT
The following command allows the user to select the type of modulated output codes generated
by the Three Channel Encoder (Assembly 55116). Each rear panel BNC connector (J3a, J3b,
J3c, J3d, J3e, or J3f) may be individually programmed. If Option 01A (DC Code Output) is
installed, see the GPS Option/Connector Configuration sheet in the User’s Guide.
To Program one channel of the Encoder:
• The user inputs $E (HEX 24) (HEX 45).
• The user inputs a digit (1 to 3) to select the specific channel.
• The user inputs a two-digit number to select the code type based on the following table:
Code Output Selection
00 = IRIG A
01 = IRIG B
02 = IRIG G
03 = IRIG E 100 Hz
04 = IRIG E 1 kHz
05 = IRIG H 100 Hz
06 = IRIG H 1 kHz
07 = XR3
08 = 2137
09 = NASA 36
• The system responds with OK CR/LF.
Example: $E102
The above example will program Channel 1 of the Three Channel Encoder to output IRIG G on
the rear panel BNC connector J3a or J3d. Refer to the GPS Option/Connector Configuration
Sheet in the User’s Guide.
If a cold reset was performed and the Three Channel Encoder was not programmed afterwards,
all three Channels will output IRIG B.
C-2 ET6xxx ExacTime GPS TC & FG (Rev C) Symmetricom Inc