APPENDIX C
1.2 OPERATION
This option has two DC inputs A and B. These dual inputs provide for a backup supply. If one
supply goes down, the other takes over. The dual inputs are diode 'ORed' together using bridge
rectifiers. Because of this, the DC input with the higher voltage will be used to power the unit.
Even though the inputs are labeled + and - , it really doesn't matter how they are connected. The
labeling is to eliminate confusion. Both inputs have 1 amp (normal blow) fuses for protection.
1.3 TEMPERATURE
The operating temperature of the unit should not exceed +40°C. This limitation is due to the fact
that there is no forced air flow over the DC-DC converter.
C-22 ET6xxx ExacTime GPS TC & FG (Rev C) Symmetricom Inc