Subject: [AVT] Re: RFC 2833 comments

From: Henning Schulzrinne <[email-masked]>
Date: Sun, 26 May 2002 23:12:42 -0400

This is an ancient email, part of my effort to get 2833 cleaned up. My 
intent is to follow the recommendation, as it simplifies things. If 
somebody either has implemented the wink, seizure and continuity tone 
events or plans to do so soon, please let me know. Otherwise, they'd 
have to go in any event once Draft Standard status looms.

I would modify the proposal below by leaving previously assigned names 
unassigned (reserved), just in case they are being used in some dark 
corner of the universe where the AVT list doesn't reach. Also, as noted, 
for testing, it's probably better to send real tones or use the tone 
facility in 2833.

Lars Tovander (EUS) wrote:

> My suggestion for trunk events is as follows:
>  
> Remove the following:
> Wink                                           160
> Wink off                                       161
> Incoming seizure                               162
> Seizure                                        163
> Unseize circuit                                164
> 
> Drop, or at least simplify, the following:
> Continuity test                                165
> Default continuity tone                        166
> Continuity tone (single tone)                  167
> Continuity test send                           168
> Continuity verified                            170
> Loopback                                       171 ???
> Old milliwatt tone (1000 Hz)                   172
> New milliwatt tone (1004 Hz)                   173
> 
> 
> My main reason for not supporting wink events is to avoid the
> added delay that would be introduced. The whole wink plus
> enough time to detect its end would be used to determine the
> event where two ABCD events with minimum delay can do 'the
> same'. Some wink 'deterioration' may occur, but that is
> better than the added delay's.
> Also, it requires the MG's to have protocol knowledge that
> they do not really need.
> 
> For Continuity/milliwatt tones it seems better to let regular tone
> transmission handle the tones.
> If the continuity tones should be supported, limit them to the
> two frequencies used (2010 and 1780 Hz) without interpretation.
> This to avoid introducing signaling knowledge in the MG's.
> The same applies to the milliwatt tones (is there really a need
> to be able to detect the difference between old and new tone?).
> 
> MF signaling:
> The frequencies for the (US) MF signals are as follows:
>   Hz  |  900 | 1100 | 1300 | 1500 | 1700
> ------+------+------+------+------+----------------
>   700 |   1  |   2  |   4  |   7  | ST3P/KP3P
>   900 |      |   3  |   5  |   8  | ST1P/KP1P
>  1100 |      |      |   6  |   9  | KP      
>  1300 |      |      |      |   0  | ST2P/KP2P
>  1500 |      |      |      |      | ST    
>  
> MFC Tones (according to ITU-T R2 MFC) (if there is a need
> to support MFC):
> /-------------------------------------------------------------\
> -        -            Frequencies in Hz                       -
> - Signal +----------------------------------------------------+
> - number - Forward  - 1380 - 1500 - 1620 - 1740 - 1860 - 1980 -
> -        +----------+------+------+------+------+------+------+
> -        - Backward - 1140 - 1020 -  900 -  780 -  660 -  540 -
> -        +----------+------+------+------+------+------+------+
> - 1      -          - X    - X    -      -      -      -      -
> - 2      -          - X    -      - X    -      -      -      -
> - 3      -          -      - X    - X    -      -      -      -
> - 4      -          - X    -      -      - X    -      -      -
> - 5      -          -      - X    -      - X    -      -      -
> - 6      -          -      -      - X    - X    -      -      -
> - 7      -          - X    -      -      -      - X    -      -
> - 8      -          -      - X    -      -      - X    -      -
> - 9      -          -      -      - X    -      - X    -      -
> - 10     -          -      -      -      - X    - X    -      -
> - 11     -          - X    -      -      -      -      - X    -
> - 12     -          -      - X    -      -      -      - X    -
> - 13     -          -      -      - X    -      -      - X    -
> - 14     -          -      -      -      - X    -      - X    -
> - 15     -          -      -      -      -      - X    - X    -
> |--------+----------+------+------+------+------+------+------/
> 
> 
> Which would leave the following trunk events:
> Event                           encoding (decimal)
> __________________________________________________
> MF 0... 9                                128...137
> MF KP (start-of-pulsing)                       138
> MF KP1/ST1                                     139
> MF KP2/ST2                                     140
> MF KP3/ST3                                     141
> MF ST (end-of-pulsing)                         142
> ABCD signaling                           143...158
> 2010 Hz tone                                   159
> 1780 Hz tone                                   160
> 1004 Hz tone                                   161
> MFC Forward 1... 15                      162...176
> MFC Backward 1... 15                     177...191     
> 
> 
>                            
> /Regards Lars.
> 
> Ericsson Inc.
> 
> Lars Tovander   M.S. A.E.          Phone: 972 583 5886
> P.O. Box 833875                    Mobile: 972 523 0827
> 1010 East Arapaho Road. MS: L-04     
> Richardson, Texas 75083-3875       SMS: [email-masked]
> mailto:[email-masked]
> 

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