From the DOCS.HP.COM website in the Using the Node Management Services (NMS)
Utilities manual

DTC
Datacommunications and Terminal Controller. The DTC is a hardware device,
configured as a node on a LAN, that enables asynchronous devices to access
HP 3000 Series 900 computers. Terminals can either be directly connected to
the DTC, or they can be remotely connected through modem or through a Packet
Assembler Disassembler (PAD).

The current HP3000 websites at HP.COM list only the 16 and 72 versions of
the DTC.  There have been other configurations in the past including the 48.
These numbers refer to the number of ports in a fully-carded DTC.  You can
get to this current information at
http://www.businessservers.hp.com/products/2_50/2_50_index.html  The older
models are a little harder to get information on the web but some
information on currently supported DTC's can be found in the MPE/iX
documentation on the http://docs.hp.com website.

Alan Wyman
White Bear Township, MN
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