Envoy ACP/XF Configuration and Management Manual

Glossary
EnvoyACP/XF Configuration and Management Manual—429232-003
Glossary-4
RTS
RTS. Request to send. A signal from the host computer or terminal (DTE) to the modem
(DCE) requesting permission to transmit data. Permission is granted when the modem
turns CTS to ON.
SABM. Set Asynchronous Balanced Mode. In ADCCP-ABM and HDLC, the unnumbered
frame sent by one station to establish a data link with another station.
SDLC. Synchronous Data-Link Control. One of the bit-synchronous communications
protocols. It uses Normal Response Mode operation and is analogous in most ways to
ADCCP-NRM. It is the protocol used in System Network Architecture (SNA) networks.
secondary. In an SDLC or ADCCP-NRM configuration, the station that is contacted by the
primary station and that is controlled by the primary message in a message exchange.
The secondary station cannot initiate a communication. See also primary.
ServerNet WAN concentrator. A six-port communications line concentrator. It replaces all
of the earlier WAN controllers, such as the 3604, 3605, 3650, and the 6100
communications controllers.
S-frame. See supervisory frame.
SNRM. Set Normal Response Mode. In ADCCP-NRM and SDLC, the unnumbered frame
sent by the primary station to the secondary station to establish the data link.
strapped. Description of the state created by a wire or clip that creates a short between two
pins.
supervisor. The controlling station in a centralized multipoint data link.
supervisory frame. A frame format used to convey READY or BUSY status or to request
retransmission when an error is detected.
SUT. Site update tape. Distribution tape for updated versions of HP-supplied software.
switched line. A line configuration for circuit-switched networks such as a public telephone
network.
synchronous. A general class of data communications that includes ADCCP, SDLC, and
HDLC protocols. It is the opposite of asynchronous communications. “Synchronous”
means that a clock signal, separate from the data signal, is used to synchronize the
receive circuits.
tributary. One of multiple stations, which are controlled by a single, centralized supervisor
station in a multipoint data link.
U-frame. See unnumbered frame.
unnumbered frame. A frame format used to pass data-link management commands and
responses between the primary and the secondary stations.