Glossary
11
Multidrop
A communication link in which a single channel is shared by several stations or nodes (DVACS is a Multidrop net-
work). Only one station may transmit at a time. Multidrop is also referred to as multipoint.
Negative Acknowl-
edgement (NAK)
See acknowledgement.
Off-Hook
The process of connecting to the telephone line to answer an incoming call or dial a remote device (answering).
On-Hook
The process of releasing the telephone line after completion of a call (hanging up).
Options
A set of user-configurable parameters which controls the operation of a device. In the System III, both the DRL3
and the CPM3 contain sets of options.
Static
options are affect all Profiles on a card.
Dynamic
options are
unique to each profile.
Packet
A group of digits or characters of information in an alarm.
Panel
A device (the alarm system) at the protected premises used to transmit alarms to the receiver.
Ping
A standard network command which can be used to verify the presence of a device on a network, using the
device IP address. Ping is implemented as part of the ICMP protocol and consists of the Echo Request and Echo
Reply commands (poll and response respectively).
POTS
Plain Old Telephone System
. An acronym used to describe a standard analog telephone network, or alterna-
tively a standard analog telephone line.
Printer Message
The alarm information delivered by a receiver to a central station printer. This information is generally encapsu-
lated in a descriptive English text message.
Profile
Generally refers to a group of options. The receiver can select a "profile" based on certain conditions.
Protocol
The pre-established order of events and meanings of the various characters in the information transmitted from
a receiver to a monitoring computer.
PSC3
Power Supply Controller 3.
PSTN
Public Switched Telephone Network
. Analogous to POTS.
PSU3
Power Supply Unit 3.
Receiver
The equipment used to receive alarms sent from panels. Sur-Gard's receivers are the SLR and the MLR. 'Receiver'
is sometimes used interchangeably with 'line card' as it is the line card which actually receives the alarm in the
MLR.
Ring
One of the wires used on a phone line, by convention this is red.
Rounds
Two or more packets of alarm information used for error checking. If two packets (rounds) are identical the
packet contains valid data.
RRLLL
The part of the automation message which stores the receiver number and line card number. The length of this
field is variable and is controlled via an option in both the line card and the CPM3.
Server
One side of a two-sided TCP socket connection. The server is the one responsible for receiving the socket con-
nection with the remote host (the client). In general, a host which acts as a server can receive multiple client
socket connection requests simultaneously. The CPM3 acts as a server to both the console and the web inter-
face.
SG
Sur-Gard, a brand name of DSC. Also used to describe a particular type of automation output.
SIA
Security Industry Association
. Sometimes referred to as the SIA format which is an example of FSK modulation.
RS-232
An asynchronous, point-to-point serial communications protocol. Used to communicate between the DRL3 and
a PC for the DRL3's debug output. Also used to communicate between the CPM3 and the automation computer,
and the CPM3 and a PC for the CPM3's debug output.
System III
Name given to a single entire receiver configuration, including rack, CPM3(s), line card(s), power supply, etc.
TCP/IP
Transmission Control Protocol/Internet Protocol.
A standard network communications protocol. On the
System III, TCP/IP is used to communicate between the console and the CPM3. It is also used to connect the
CPM3 to a TCP printer (resident on the console) and TCP automation software (runs independent of the con-
sole).
Tip
One of the wires used on a phone line, by convention this is green.
UIB3
User Interface Board 3. An L-shaped board which connects to the CPM3 and contains output LEDs and 4 push
buttons used for the user interface. This board also connects directly to the LCD screen.
Zone
The portion of an alarm which contains the information identifying the specific zone of the panel that has been
violated.