PCM20H ARCNET Network Interface Modules (NIMs) were discontinued in 2006 when
Contemporary Controls switched to lead-free manufacturing.
The PCM20H Series of NIMs linked PC Card compatible computers with the
ARCNET local area network, allowing a connection to laptop and
notebook-style computers.
These NIMs followed PC Card standard 2.1 for Type II (5.0 mm thick) cards. The
ARCNET transceiver circuitry was located in a detachable MAU (Medium Access
Unit) which plugged into the PCM20H adapter. MAUs existed for various
cabling media including coaxial and twisted-pair cable, and were all
interchangeable with one another. A 15-pin connector with a short cable
attached the MAU to the adapter. The PCM20H featured the COM20022 ARCNET
controller chip, offering data rates up to 10 Mbps.
There were six models, each designated by a specific transceiver. The PCM20H-CXB
supported coaxial star or bus networks. Two models accommodated traditional
ARCNET over twisted-pair cabling using different connectors: the PCM20H-TB5
used the RJ-45 connector and the PCM20H-TPB used the RJ-11 connector. Four
models supported the EIA-485 protocol: the DC-coupled PCM20H-485D and the
AC-coupled PCM20H-485X implemented backplane mode automatically via built-in
hardware, the DC-coupled PCM20H-485 allowed the backplane mode to be set via
software.
The product originally shipped with a 3.5" (9 cm) disk that contained our DOS,
Windows 3.x and Windows 95/98 enabler software.
