6100 ADCCP Programming Manual

Glossary
Glossary–2 069225 Tandem Computers Incorporated
CIU. See communication interface unit (CIU).
clear to send (CTS ). A signal that comes from a modem, indicating to the computer that
the modem is ready to accept data for transmission.
CLIP. See communications line interface processor (CLIP).
CMI. See Communications Management Interface (CMI).
communication interface Unit (CIU). The proper term used for the 6100/3650 family of
controllers. There can be two of these programmable I/O controllers in each 6100 CSS
or 3650 CSS; the CIUs connect the host with the rest of the 6100 communications
subsystem (CSS) or 3650 CSS. These CIUs are another fault-tolerant Tandem
enhancement: if one of the CIUs fails, the other takes over.
Communications Subsystem Manager (CSM).. A software process within the CPU that
coordinates certain functions within the 6100 subsystem. Among other things, the
CSM can load special microcode into the communications interface units (CIU) and
communications line interface processors (CLIP). The CSM also monitors the physical
environment of the 6100 CSS.
communications line interface processor (CLIP). The CLIP is part of the line interface unit
(LIU) within the 6100/3650 family of controllers. The CLIP is a programmable
processor that provides a link-level protocol and a software interface to the host. The
CLIP does some of the work that the host-resident communication processes used to
handle. CLIP software implements specific communications protocols such as
advanced data communications control procedures (ADCCP) or TINET.
communications management interface (CMI). The CMI, together with its server process,
the communications management process (CMP), provides the main operator interface
to CP6100. Through CMI, a user can issue commands to change the subsystem
configuration or inquire about the characteristics and status of lines.
control field. The field following the address field in a bit-synchronous frame.
It contains bit-encoded commands and responses and can also contain frame sequence
numbers. The contents of the control field indicate whether the frame has an
information, supervisory, or unnumbered format. Generally, this field is 1 octet long;
however, in extended mode, the control field can be 2 octets long.
CSM. See Communications Subsystem Manager.(CSM).
CTS . See clear to send (CTS).
data carrier detect (DCD). A signal that comes from a modem indicating that a data
carrier is being received. On half duplex channels, this signal is off whenever RTS is
on.
data set ready (DSR). The signal sent by a modem to the line informing the calling DCE
that the unit received a DTR signal from the associated DTE.
data-circuit terminating equipment (DCE). Generally refers to the modem to which a
terminal or host computer (called the DTE) is connected.