Telenetics 2185 manual Glossary-2

Telenetics 2185

Controller	Device responsible for polling terminals and routing
	messages in a multipoint environment.
Control Signal	Subchannels contend for use of the main channel to
Contention Mode	send data to the CPU or controller. In the control
	signal contention mode, subchannel devices contend
	by raising control signal RTS if the device is a DTE,
	or control signal DCD if the device is a DCE. The
	2185 DSD returns CTS to a selected subchannel
	device. The selected subchannel disconnects from
	the main channel when the subchannel device drops
	RTS or DCD.
DATA	LED indicator lamp that illuminates when the main
	channel inbound data is aSPACE.
Data Contention	Subchannels contend for use of the main channel to
	send data to the CPU or controller. In the data
	contention mode, a subchannel contends for access
	to the main channel by sending data (beginning with
	a space bit). The selected subchannel disconnects
	from the main channel after 16 consecutive mark
	bits are detected.
Modem-Sharing	In the modem-sharing mode, the CPU or controller
	is at a site remote from the 2185. The 2185's main
	channel connects to the CPU through a modem link
	(DCE). Subchannel terminals are connected
	directly to the 2185 DSD.
Multipoint	A communications arrangement where multiple
	devices share a common transmission channel,
	though only one device may transmit at a time.
	Such networks usually require some kind of polling
	mechanism, which is under the control of a master
	station, to ensure that only one device transmits data
	at a time. Also known as a multidrop network.
Port	Physical point of access into a computer, a network,
	or other electronic device.
Port-Sharing	In the port-sharing mode, the 2185's main channel is
	connected directly to a CPU or controller port
	(DTE). Subchannel devices communicate with the
	2185 DSD via modem links.

Glossary-2