Glossary - 7
PCMCIA. Personal Computer Memory Card Interface Association. See PC Card.
Percent Decode. The average probability that a single scan of a bar code would result in a successful decode. In a
well-designed bar code scanning system, that probability should approach near 100%.
PING. (Packet Internet Groper) An Internet utility used to determine whether a particular IP address is online. It is used to
test and debug a network by sending out a packet and waiting for a response.
Print Contrast Signal (PCS). Measuremen t of the contrast (brig ht ne ss dif f erence) between the bars and spaces of a
symbol. A minimum PCS value is needed for a bar code symbol to be scannable. PCS = (RL - RD) / RL, where RL is
the reflectance factor of the background and RD the reflectance factor of the dark bars.
Programming Mode. The state in which a scanner is configured for parameter values. See Scanning Mode.
Q
Quiet Zone. A clear space, containing n o dark marks, which pr ecedes the start character of a b ar code symbol and follows
the stop charac te r.
QWERTY. A standard keyboard commonly used on North American and some Euro pean PC keyboards. “QWERTY” r efers
to the arrangement of keys on the left side of the third row of keys.
R
RAM. Random Acce ss Mem or y. Data in RAM can be ac ce sse d in ra nd o m or der, and quickly written an d read .
Reflectance. Amoun t of ligh t returned from an illuminated surface.
Resolution. The narrowe st element dimension which is distinguished by a particular readin g de vic e or prin te d with a
particular device or method.
RF. Radio Frequency.
ROM. Read-Only Memory. Data stored in ROM cannot be changed or removed.
Router. A device that connects networks and supports the required protocols for packet filtering. Routers are typically used
to extend the range of cabling and to organize the topology of a network into subnets. See Subnet.
RS-232. An Electronic Industrie s Association (EIA) standard that defi nes the connector, connector pins, and signals used to
transfer data serially from one device to another.
S
Scan Area. Area intended to contain a symbol.