This document describes tools that were developed
at Gallaudet University to support field studies of TTY transmission
over digital wireless telephones. They are being distributed to
the TTY Forum in the hope that they may be of some use to companies
testing TTY over wireless networks in field conditions.
This is not a test plan, but simply some tools for testing.
The tools permit semi-automated data collection
in mobile conditions. A laptop or notebook computer is attached
by serial cable to a model of TTY that consumers would typically use
for wireless telephone conversation.
Using the data collection software, Mobile TTY
Test Software, the tester can launch bi-directional scripts, which
will alternate sides automatically after the GA characters. The text
passes via serial connection to the TTY and then via audio connection
to the handset. Incoming text is captured from the TTY by the
laptop.
Data on call conditions can be entered into the
data collection software, and these conditions along with a time stamp
are saved into a database format suitable for import to Excel or
similar software. The software separates the two sides of the
conversation for separate scoring of each side.
This is done to assist in diagnosis of errors.
SCORE by Lober and Walsh (licensed for use by the
TTY Forum in testing TTYs over wireless telecommunications), and
CTM_SCORE (from 3GPP TS 26.231 CTM Minimum Performance Specification)
are supported; a utility program provided in the Gallaudet package
runs both scoring programs and integrates the output with data on call
conditions supplied by the tester.
Wireless-to-wireline or wireless-to-wireless calls are supported,
depending on the number of modified TTYs available (two are needed for
wireless-to-wireless calls).
Test scripts are provided. The scripts are intended to represent
natural conversations of the type consumers will have using TTY over
wireless telephones.
The set-up is straightforward. The documentation is written in (excruciating) detail so that
even a non-engineer can do the set-up.
The most
recent version of the Gallaudet TTY tools, including
documentation, software, scoring programs, and scripts is
available from ATIS (Alliance for Telecommunications Industry
Solutions) at http://www.atis.org/atis/atisinfo/ttsi/ttsitesting.htm.
Note that this page is password protected. You must
contact Bill Breslin at wbreslin@atis.org
to register.
Or you can download our version 1.11 including document from here.
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