Telecommunications Industry Association
TR41.3.12-10-11-005
Document Cover Sheet
Project Number
PN-3-4350.330-RV3
Document Title
DTMF Digit Recognition Testing Procedures
Source
Advent Instruments Inc.
Contact
David Stenner
Suite 111, 1515 Broadway St.
Port Coquitlam, BC, Canada, V3C6M2
Distribution
TR-41.3.12
Intended Purpose
of Document
(Select one)
X
Phone: 604-944-4298 ext 2002
Fax: 604-944-7488
Email: d_stenner@adventinst.com
For Incorporation Into TIA Publication
For Information
Other (describe) -
The document to which this cover statement is attached is submitted to a Formulating Group or
sub-element thereof of the Telecommunications Industry Association (TIA) in accordance with the
provisions of Sections 6.4.1–6.4.6 inclusive of the TIA Engineering Manual dated October 2009, all
of which provisions are hereby incorporated by reference.
Abstract
This contribution consists of the proposed wording for the Method of Measurement section in DTMF
Recognition section (4.5.3.1.2) of the TAM draft standard. The basic procedure outlined is to first start
with all parameters set at nominal. Then adjust the frequency, level, twist, and duration parameter of each
digit one at a time to the extremes of the acceptable range. Finally the minimum inter-digit interval is
tested between 12 successive digits with all other parameters at nominal.
v1.0 – 20050426
Telecommunications Industry Association
4.5.3.1.2
TR41.3.12-10-11-005
Method of Measurement
For each of the DTMF digits the following test is performed to test the recognition of the digit by
the TAD. One parameter at a time is adjusted while the others remain at the nominal or the
center value in the range listed in section x.x.x.x.x. The digit duration for the test is 70ms except
in step 5.
1. Nominal Values Test: Set all of the parameters to the nominal or center value and confirm
digit recognition.
2. Frequency variation Test:
2.1. Adjust the low frequency component to -1.5% and confirm digit recognition.
2.2. Adjust the high frequency component to -1.5% and confirm digit recognition.
2.3. Adjust the low frequency component to +1.5% and confirm digit recognition.
2.4. Adjust the high frequency component to +1.5% and confirm digit recognition.
3. Amplitude variation Test:
3.1. Adjust the low frequency and high frequency tones to -37 dBm per tone and confirm
digit recognition.
3.2. Adjust the low frequency and high frequency tones to -3 dBm per tone and confirm digit
recognition.
3.3. Adjust the low frequency and high frequency tones to -43 dBm per tone and confirm that
the digit is not recognized.
4. Twist Variation Test
4.1. Adjust the low frequency tone to -20 dBm and the high frequency tone to -28 dBm and
confirm digit recognition.
4.2. Adjust the low frequency tone to -20 dBm and the high frequency tone to -16 dBm and
confirm digit recognition.
5. Digit duration
5.1. Adjust the duration of the digit to 100 ms and confirm the digit recognition.
5.2. Adjust the duration of the digit to 1000 ms and confirm the digit recognition.
6. Inter-digit test between multiple digit.
6.1. Generate a string of 12 DTMF digits with an inter-digit delay of 50ms and confirm digit
string recognition.
.
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