thing like what follows. What is important is that you get the information from an ether cable over the network and you must specify the address of a “NIS server” that is running NIS (not the Master/Slave networking de- scribed above). The NIS slave apcupsd will then poll the NIS server at the NETTIME interval you specify to obtain the status.

Here are a few words from Adam Kropelin concerning the difference between the Master/Slave networking and the NIS-based networking:

Think of the difference as push (Master/Slave) vs. pull (NIS-based). In the case of M/S, the master makes all the shutdown decisions and notifies the slaves when they are to shut down or when some other interesting event happens. The slaves just do whatever the master says, whenever the master says to. On the other hand, with the NIS-based network config you basically “publish” the UPS status from one server and then your clients view that status and make their own decisions.

Personally, I like the NIS-based approach because the master knows nothing about the slaves, thus there are fewer configuration files to keep in sync. I also like the flexibility of allowing each slave to make its own decision on when to shut down; some of my old clunker servers take quite a long while to shut down. There are problems reported occasionally with the M/S approach, where slaves sometimes lose contact with the master or vice- versa. I know improvements have been made in that code, but I still like the simplicity of using NIS.

Another thing to think about is how you feel about running a network service like NIS on your firewall. My network is set up almost identically to yours and I chose to run the apcupsd “master” on a server in the DMZ and have the firewall just be a client of it. That way I don’t have to run NIS on the firewall apcupsd instance.

## apcupsd.conf v1.1 ## UPSCABLE ether UPSTYPE net

LOCKFILE /var/lock

DEVICE server-network-address:3551 UPSCLASS standalone

UPSMODE disable NETTIME 10

where on the DEVICE directive you replace the server-network-address with the fully qualified domain name or IP address of a machine running apcupsd with NIS enabled (and normally, but not required, connected to a

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APC UPS control system manual Upsmode disable Nettime
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UPS control system specifications

APC UPS (Uninterruptible Power Supply) control systems are vital components for ensuring uninterrupted power supply and protecting critical equipment from power interruptions, surges, or fluctuations. Designed by Schneider Electric, APC UPS systems are renowned for their high quality and reliability. They utilize advanced technologies and features to suit diverse applications, from home offices to large industrial settings.

One of the main features of APC UPS systems is the ability to provide backup power during outages. This is achieved through a battery system that activates immediately when the mains power fails. This seamless transition minimizes downtime and ensures that electronic devices continue to operate, protecting data integrity and equipment lifespan.

Another significant characteristic of APC UPS systems is their intelligent management capabilities. Most models come with PowerChute software, which provides users with real-time monitoring of power conditions and the status of the UPS. This software allows for graceful shutdowns of connected devices during extended outages, thereby preventing data loss and damage to devices.

APC UPS systems also incorporate advanced technologies such as Automatic Voltage Regulation (AVR). AVR technology ensures that the output voltage remains stable by correcting minor fluctuations without switching to battery mode. This not only prolongs the battery life but also provides a consistent power supply to the connected equipment.

Thermal management is another critical aspect of APC UPS control systems. The design often includes efficient cooling systems that prevent overheating, ensuring optimal performance and longevity of the unit. Some models feature EcoMode, which reduces energy consumption and lowers operational costs by working at high efficiency only when battery backup is not required.

APC UPS systems are designed with scalability in mind. Users can easily add more batteries or connect additional UPS units to accommodate growing power needs. Features such as hot-swappable batteries and modular design facilitate easy upgrades and servicing without interrupting power supply.

In terms of connectivity, APC UPS products often feature multiple options including USB, RS-232, and network management capabilities. This enables users to connect remote management tools and integrate the UPS with existing IT infrastructure.

In summary, APC UPS control systems deliver reliability, efficiency, and advanced technology features that cater to a wide array of power protection needs, making them a trusted choice for individuals and businesses alike.
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