Symbol Technologies MC50 - Manual (Page 90)

MC50 User Guide GL-10
PC Card A plug-in expansion card for laptop computers and other devices,
also called a PCMCIA card. PC Cards are 85.6mm long x 54 mm
wide, and have a 68 pin connector. There are several different
kinds:
Type I; 3.3 mm high; use - RAM or Flash RAM
Type II; 5 mm high; use - modems, LAN adaptors
Type III; 10.5 high; use - Hard Disks
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) Measurement of the contrast (brightness difference) 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.
Quiet Zone A clear space, containing no dark marks, which precedes the start
character of a bar code symbol and follows the stop character.
QWERTY A standard keyboard commonly used on North American and some
European PC keyboards. “QWERTY” refers to the arrangement of
keys on the left side of the third row of keys.
RAM Random Access Memory. Data in RAM can be accessed in random
order, and quickly written and read.
Reflectance Amount of light returned from an illuminated surface.
Resolution The narrowest element dimension which is distinguished by a
particular reading device or printed with a particular device or
method.
RF Radio Frequency.
ROM Read-Only Memory. Data stored in ROM cannot be changed or
removed.
ROM-DOS The name of the licensed Disk Operating System loaded into the
mobile computer’s flash file system.
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 Industries Association (EIA) standard that defines the
connector, connector pins, and signals used to transfer data serially
from one device to another.
Scan Area Area intended to contain a symbol.