Intel PXA27 Series Design Manual page 290

Glossary
TAP. Test Access Port. The boundary-scan interface provides a means of driving and sampling the external pins of
the processor: testing the processor's electrical connections to the circuit board and the integrity of the circuit board
connections between devices. The interface is controlled through five dedicated TAP pins.
TC. Temperature Cycling
TCK. Test Clock
TDD. Time Division Duplexing. The Mobile Station and the Base Station transmit on same frequency at different
times.
TDM. See Time Division Multiplexing.
TDMA. Time Division Multiple Access
TDMA. Protocol allows multiple users to access a single radio frequency by allocating time slots for use to
multiple voice or data calls. TDMA breaks down data transmissions, such as a phone conversation, into fragments
and transmits each fragment in a short burst, assigning each fragment a time slot. With a cell phone, the caller
would not detect this fragmentation. TDMA works with GSM and digital cellular services.
TDR. See Time Domain Reflectometer.
Termination. Passive components attached at the end of cables to prevent signals from being reflected or echoed.
Three-state. A high-impedance state in which the output is floating and is electrically isolated from the buffer's
circuitry.
Time Division Multiplexing (TDM). A method of transmitting multiple signals (data, voice, and/or video)
simultaneously over one communications medium by interleaving a piece of each signal one after another.
Time Domain Reflectometer (TDR). An instrument capable of measuring impedance characteristics of the USB
signal lines.
TFT. Thin Film Transistor. An active LCD panel in which each pixel is controlled by individual transistors that
allows the voltage applied to each pixel to be precisely controlled. This permits faster response time and greater
contrast compared to passive LCD panels.
Time-out. The detection of a lack of bus activity for some predetermined interval.
Token Packet. A type of packet that identifies what transaction is to be performed on the bus.
TPV. Third Party Vendor
Transaction. The delivery of service to an endpoint; consists of a token packet, optional data packet, and optional
handshake packet. Specific packets are allowed/required based on the transaction type.
Transaction translator. A functional component of a USB hub. The Transaction Translator responds to special
high-speed transactions and translates them to full/low-speed transactions with full/low-speed devices attached on
downstream facing ports.
Transfer. One or more bus transactions to move information between a software client and its function.
Transfer Type. Determines the characteristics of the data flow between a software client and its function. Four
standard transfer types are defined: control, interrupt, bulk, and isochronous.
TS. Thermal Shock
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Glossary-14 Intel PXA27x Processor Family Design Guide