Spectra Precision ProMark 800 Reference Manual - Manual (Page 86)

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RTK Implementation
CSD: Circuit Switched Data. CSD is the original form of data
transmission developed for the Time Division Multiple Access
(TDMA)-based mobile phone systems like GSM.
Direct IP: (IP=Internet Protocol). A way of acquiring base
data from the Internet via a network connection to a static IP
address.
GPRS: General Packet Radio Service. A mobile data service
available to GSM modem users such as cell phone users.
GPRS data transfer is typically charged per megabyte of
transferred data, while data communication via traditional
circuit switching is billed per minute of connection time,
independent of whether the user has actually transferred data
or has been in an idle state.
GSM: Global System for Mobile communications. A
widespread standard for mobile communications based on
TDMA (Time-Division Multiple Access) technology.
Modem: A device that modulates an analog carrier signal to
encode digital information, and also demodulates such a
carrier signal to decode the transmitted information.
NTRIP: Networked Transport of RTCM via Internet Protocol.
A protocol used by GNSS service providers to deliver
corrections from their networks of reference stations (bases).
NTRIP Caster: A piece of software in charge of collecting data
from a network of Internet-connected bases using the NTRIP
protocol and responding to a rover request by routing RTK
correction data from the desired base to the calling rover.
Rover requests are addressed to the caster via a network
connection.
Source Table: Refers to a caster. The source table lists the
characteristics of all the bases managed by the caster.
TCP/IP Direct: Designates a network connection in Direct IP
mode that includes secure data exchange mechanism
between the different units involved (about 90% of the
connections available in Direct IP mode).
Transfer Rate: The interval at which a base is set to transmit
its RTK correction data. Usually expressed in seconds.
UDP/IP Direct: Designates a network connection in Direct IP
mode in which data exchange only relies on the use of IP
addresses and port numbers (unlike TCP/IP Direct, there is no
secured data exchange mechanism; about 10% of the
available connections in Direct IP mode).