Ant	GPS Antenna: High Performance GPS Antenna for harsh RF Environments.
B	Parallel BCD Output: CMOS compatible, 5-volt logic in parallel four-line format. Specify the ES-169B.
BBU	Battery Back-Up: An internal Gel-Cell battery is provided capable of maintaining the unit's microprocessor for up to a 4-hour power outage.
DC	DC Operation: Requires the unit to be powered from a DC source exclusively, typically +12 to +35 VDC.
EX10	External Time Base: Available when a user prefers to reference the clock of an existing source of 10 MHz.
HR	Relay Closure: Option "HR" provides a user programmable relay contact closure. The standard contact closure occurs on the Hour and Half Hour. If contact closures at other times are desired, the user can program up to four relay closures using the PC Software, which can be downloaded from the ESE web site. The reed relay is rated at 10 watts maximum resistive load (500 mA switching current) and is intended for control applications only. The relay contacts are accessible on the DB-9 connector.
K	Provides a 10 MHz output and a phase lock 1PPS signal.
MG	Multi-GNSS: Provides a Multi-GNSS Receiver capable of tracking multiple Global Navigation Satellite Systems.
OCXO	OCXO: Provides an Oven Controlled Crystal Oscillator.
UL	"UL" Approved Power Supply: The unit is supplied with a UL/CSA approved wall mount power supply (90-264 VAC).