The PCX20 incorporates the COM20020 ARCNET controller chip with advanced features over earlier ARCNET chips; namely command chaining, sequential access to internal RAM, duplicate node ID detection and variable data rates up to 5 Mbps. Bus contention problems are lessened since the module only needs an I/O address. There is no requirement for wait-state arbitration.

Each PCX20 module has two LEDs on the board for monitoring network operation and bus access to the module. It also has an external DIP switch so that node addresses can be easily reassigned without removing the module.

There are several versions of the PCX20 series. The PCX20-CXS supports coaxial star configurations requiring external active or passive hubs. The PCX20-CXB accommodates a multidrop or coaxial bus configuration typically without any hubs. Other versions include the PCX20-FOG for fiber optic cable with either ST or SMA connectors. The PCX20-TPB supports multidrop twisted-pair cabling using RJ-11 and screw terminal connectors. The PCX20-485 has EIA-485 DC coupled backplane operation, while the PCX20-485D supports non-backplane mode DC EIA-485. The PCX20-485X is designed for transformer-coupled EIA-485 operation.

Features

• Utilizes COM20020 ARCNET controller
• Interfaces ARCNET with PC/XT/AT (ISA) bus computers
• I/O-only mapping reduces bus contention problems
• No requirement for wait-state arbitration
• Deterministic, high-speed ARCNET token-passing local area network (LAN)
• Enhanced software capabilities over earlier generation ARCNET controllers
• Supports coaxial, fiber optic and twisted-pair cabling including EIA-485
• Node address switch selects one of 255 possible station addresses
• Variable data rates up to 5 Mbps
• Suitable with all the Contemporary Controls' MOD HUB and AI series active hubs
• CMOS design for low-power consumption