[asterisk-bugs] [Zaptel 0003676]: Parallel pulse dialing phone causing false ZT_RXSIG_RING signal on TDM400P FXO

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=3676 
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Reported By:                tdacosta
Assigned To:                markster
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Project:                    Zaptel
Issue ID:                   3676
Category:                   wctdm
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     closed
Zaptel Version:             CVS HEAD 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
Resolution:                 fixed
Fixed in Version:           
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Date Submitted:             02-26-2005 15:46 CST
Last Modified:              06-07-2008 10:49 CDT
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Summary:                    Parallel pulse dialing phone causing false
ZT_RXSIG_RING signal on TDM400P FXO
Description: 
When a **pulse** dialing telephone is attached to a Canadian telco
line(Telus) in parallel with a TDM400P FXO port, using the phone to dial
out causes wcfxs to detect a false ring signal on the FXO port.  The
problem can be traced to wcfxs setting the ring detect threshold too low. 


The telco line applies 48V battery onhook which drops to about 6V in the
offhook state.  Pulse dialing creates a 10Hz 42Vpp waveform in this case. 
The RMS voltage value of the waveform that I measured is about 19V.  

Currently, wcfxs initializes the Si3050 ring threshold to 13.5V-16.5VRMS. 
This should be changed to the next available level of 19.35V-23.65VRMS.

The change involves changing the 'rt' item in the fxo_modes structure to a
value of 1, instead of 0, as shown here:

fxo_modes[] =
{
	{ "FCC", 0, 0, 0, 1, 0, 0x3, 0, 0 }, 	/* US, Canada */ 

Attached waveform plots are made using a 10X scope probe, so all voltage
must be scaled by 10.
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---------------------------------------------------------------------- 
 svnbot - 06-07-08 10:49  
---------------------------------------------------------------------- 
Repository: dahdi
Revision: 598

U   trunk/wctdm.c

------------------------------------------------------------------------
r598 | markster | 2008-06-07 10:49:10 -0500 (Sat, 07 Jun 2008) | 2 lines

Fix ringer not to catch pulse dial pulses (bug
http://bugs.digium.com/view.php?id=3676)

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http://svn.digium.com/view/dahdi?view=rev&revision=598 

Issue History 
Date Modified   Username       Field                    Change               
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06-07-08 10:49  svnbot         Checkin                                      
06-07-08 10:49  svnbot         Note Added: 0088013                          
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