Although data loggers are commonly used for long term measurement, it's also possible to use standard PCs for the same purpose by installing dedicated input/output cards to the PCI slots and using third-party measuring and control software. Similarly, PCs can be used as soft PLCs, provided suitable interface cards are installed. The most common type of I/O card is a digital I/O PCI card. These cards are installed into the PCI slots fitted to desktop computer mother boards. PCI stands for Peripheral Component Interconnect, and there are several versions that are backward compatible. When selecting a PCI card, it's important to ensure it is compatible with the computer mother board. A typical digital PCI card may have 32 digital inputs or outputs, and connection is through an appropriately-sized D-sub connector. Analogue I/O PCI cards are used to measure and convert analogue inputs, such as temperature and pressure, into a digital format. The resolution of each card is determined by the number of bits. Cards may be input only, output only or a combination of input and output, and even include a digital input and output capability. Another form of digital card is the digital ISA card. Suppliers of I/O cards include Advantech and Addi-Data.