| NTP | NTP Time Server. Specify ES-299A IRIG Based NTP Server, connected externally. |
| B | Parallel BCD Output: CMOS compatible, 5-volt logic in parallel four-line format is accessible through a rear-mounted D-sub connector. |
| Clear | Clear Anodized Front Panel |
| HR | Relay Contact Closure: A contact closure occurs at the top of each Hour. Hour and 1/2 Hour closure may be ordered on some products. Relay contacts are rated at 10-Watts maximum load, 500mA maximum switching current. |
| J | 220 VAC/50 Hz Operation: The unit is configured to operate from 220 VAC line voltage. 117 VAC 50/60 Hz is standard. |
| UL | "UL" Approved Power Supply: The unit is supplied with a UL/CSA approved wall mount power supply. |