and information graciously supplied by APC. Hopefully, the additions made herein can benefit the original author and his programming project, and maybe some day, the apcupsd project and the NUT project can join forces.

Description

Here’s the information on the elusive APC smart signaling protocol used by their higher end units (Back-UPS Pro, Smart-UPS, Matrix-UPS, etc). What you see here has been collected from a variety of sources. Some people analyzed the chatter between PowerChute and their hardware. Others sent various characters to the UPS and figured out what the results meant.

RS-232 differences

Normal 9 pin serial connections have TxD on 3 and RxD on 2. APC’s smart serial ports put TxD on pin 1 and RxD on pin 2. This means you go nowhere if you use a normal straight through serial cable. In fact, you might even power down the load if you plug one of those cables in. This is due to the odd routing of pins - DTR and RTS from the PC usually wind up driving the on/off line. So, when you open the port, they go high and *poof* your computer dies.

Originally this evil hack was used to connect the UPS to the PC when this page was first being built. As you can see, I cheated and neglected the ground (only 2 wires!) and it still worked. This method can be used for playing around, but for professional systems this is obviously not a viable option.

That hack didn’t work out so well (damned cats), so it was retired quite awhile back. The most practical solution was to go out and BUY the DOS/Win version of PowerChute just for the black (smart) cable. I rec- ommend doing the same thing if you actually care about this thing working properly. Of course, if you have one of the newer packages that came with PowerChute, you already have the cable you need.

Diagram for cable hackers

If you are handy with cable creation tools, check out the

940-0024C clone diagram. That’s the black “smart” cable normally provided with APC models sold after 1996. The loopback pins on that

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APC UPS control system manual Description, RS-232 differences, Diagram for cable hackers
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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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