Consortium introduced a newer standard based on the PCI bus. A PCI Express-based standard was introduced in 2008. PC/104-related specifications are controlled by the PC/104 Consortium. There are currently 47 members of the Consortium. All specifications published by the Consortium are freely available. Membership in the Consortium is not required to design and manufacture a PC/104 board. Bus structure vis-à-vis form factor The specifications released by the PC/104 Consortium define multiple of Bus Structures (ISA, PCI, PCI Express) and Form Factors (104, EBX, EPIC). Bus Structure defines the location and pinout of the bus connector(s). Form Factor refers to size and shape of the board. It is possible to find one of the PC/104 stackable expansion buses on a number of different form factors. While most commercially available products using the Bus Structures will comply with the Form Factors listed below, it is possible for a non-standard or proprietary form factor to incorporate one of the PC/104 Bus Structures for expandability. Note the term "PC/104" is often used interchangeably to refer to either the Bus Structure or Form Factor. This can be a source of confusion. For example, a product datasheet may refer to a board as "PC/104" due to its size and shape when it in fact has a PCI-104 expansion bus. Bus structures The PC/104 Consortium specifications define a variety a computer buses, all of which derive from the ISA, PCI, and PCI Express buses found in a desktop PC. PC/104 The original PC/104 bus derives from the ISA bus. It includes all the signals found on the ISA bus, with additional ground pins added to ensure bus integrity. Signal timing and voltage levels are identical to the ISA bus, with lower current requirements. The PC/104 specification defines two versions of the bus, 8-bit or 16-bit. The 8-bit version corresponds to the IBM XT and consists of 64 pins. The 16-bit version corresponds to the IBM AT and adds 40 additional pins, bringing the total to 104 (hence the name "PC/104"). The signals marked J1/P1 are only found on the 8-bit version, while the 16-bit version adds the signals of J2/P2. Since PC/104 is based on the ISA bus, it is often necessary to set the Base Address, IRQ, and DMA channel when installing a peripheral board. This is usually accomplished via the use of jumpers or DIP switches on the peripheral board. Failure to configure the peripheral