IRIG-B	IRIG-B Input: The "Impulse" circuitry is replaced with the IRIG-B input. (Not available with LX-5105U/Light)
LIGHT	Lighted Dial: Available only on the LX-5100 Series Analog Clocks. The dial of the clock can be illuminated. A brightness control switch (or dial for non-U versions) is included. (Not available with the LX-5105U/IRIG-B)
NTP6-C	NTP Client: NTP Client Displays synchronize exclusively with an NTP server (replaces all standard inputs).
P	19" Front Panel (Rack Mount), this unit will be 8RU.
PoE	Receives 48V operating power via Ethernet cable.