User`s guide

Appendix A Glossary of Network Terms and Internet Protocols
Network Terms and Definitions
LanScaperPRO Network Tester User’s Guide 77
NIC (Network Interface Card)
Typically an option card plugged into a PC card slot that
provides an Ethernet interface for that PC. LanScap-
erPRO uses the term NIC to define the connector pin out
that allows for direct connection to a hub device using a
straight-through cable.
Polarity
Ethernet transmit and receive driver chips use differential
voltages to improve noise immunity. Thus each direction
of transmission uses a pair of wires, one for the positive
(+) side and the other for the negative (-) side. Early
Ethernet interface chips were not designed to recognize
and compensate for reversed cable pairs, so a crossed
(+) and (-) pair could cause problems. Modern Ethernet
chips can compensate, so the wiring is not critical, but the
LanScaperPRO can determine the difference, and will
report it.
Power over Ethernet (PoE)
A method of providing power to remote devices such as
IP telephones, WiFi access points, or IP cameras using
the Ethernet cable. The IEEE has standardized a method
for safely detecting compatible equipment and providing
that power in their IEEE 802.3af specification. Cisco
Systems developed a method of providing PoE prior to the
IEEE specification and their method is called Cisco In Line
(ILP) power. The devices that provide the power are
termed Power Source Equipment (PSE) and the devices
that use the power are called Powered Devices (PD). Both
of these PoE methods can provide power using either the
LanScaperPRO_User_Guide.book Page 77 Friday, January 25, 2008 1:14 PM