Electrical, Mechanical, and Thermal Specification
Glossary-7
Intel PXA270 Processor
Glossary
IMMU:
Instruction Memory Management Unit, part of the Intel XScale core.
I-Mode:
A Japanese wireless service for transferring packet-based data to handheld devices created by NTT
DoCoMo. I-Mode is based on a compact version of HTML and does not currently use WAP.
I-cache:
Instruction cache
IBIS:
I/O Buffer Information Specification is a behavioral description of the I/O buffers and package
characteristics of a semiconductor device. IBIS models use a standard format to make it easier to import data into
circuit simulation software packages.
iDEN:
Integrated Digital Enhanced Network. A technology that allows users to access phone calls, two-way radio
transmissions, paging and data transmissions from one wireless device. iDEN was developed by Motorola and
based on TDMA.
Interrupt Request
(IRQ): A hardware signal that allows a device to request attention from a host. The host
typically invokes an interrupt service routine to handle the condition that caused the request.
Interrupt Transfer:
One of the four USB transfer types. Interrupt transfer characteristics are small data,
non-periodic, low-frequency, and bounded-latency. Interrupt transfers are typically used to handle service needs.
See also
transfer type
.
I/O Request Packet:
An identifiable request by a software client to move data between itself (on the host) and an
endpoint of a device in an appropriate direction.
IrDA:
Infrared Development Association
IRP:
See I/O Request Packet.
IRQ:
See Interrupt Request.
ISI:
Inter-signal interference. Data ghosting caused when multi-path delay causes previous symbols to interfere
with the one currently being processed.
ISM:
Industrial, Scientific, and Medical band. Part of the wireless spectrum that is less regulated, such as 802.11.
Isochronous Data:
A stream of data whose timing is implied by its delivery rate.
Isochronous Device:
An entity with isochronous endpoints, as defined in the USB Specification, that sources or
sinks sampled analog streams or synchronous data streams.
Isochronous Sink Endpoint
:
An endpoint that is capable of consuming an isochronous data stream that is sent by
the host.
Isochronous Source Endpoint:
An endpoint that is capable of producing an isochronous data stream and sending
it to the host.
Isochronous Transfer:
One of the four USB transfer types. Isochronous transfers are used when working with
isochronous data. Isochronous transfers provide periodic, continuous communication between host and device. See
also
transfer type
.
Jitter:
A tendency toward lack of synchronization caused by mechanical or electrical changes. More specifically,
the phase shift of digital pulses over a transmission medium.
kb/s:
Transmission rate expressed in kilobits per second. A measurement of bandwidth in the U.S.