Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-05 Thread Ryan Courtnage
On 3-May-05, at 9:16 PM, Henry Devito wrote:
Nortel and Toshiba and so on help eliminate this by routing  
outgoing calls starting from the highest trunk backwards and  
incoming calls of course start from the lowest trunk and work upward.
Thanks for everyone's feedback on this.
Just to add closure to the discussion, Zap channel groups support  
this hunting by use of a group number prefix in the dial cmd:
http://voip-info.org/wiki-Asterisk+ZAP+channels

Dial(Zap/g2...): Looks in order 1, 2, 5, 8
Dial(Zap/G2...): Looks in order 8, 5, 2, 1
Dial(Zap/r2...): Looks in order 8, 1, 2, 5
Dial(Zap/R2...): Looks in order 2, 1, 8, 5
(I was previously only aware of g).
Thanks
Ryan


Ryan Courtnage wrote:

Hello all,
Everyone has probably experienced this at some point in the past:
You pick up your analog phone.  Rather than hearing dialtone,  
you  are connected with someone who has just called you.   
Neither you  nor them heard a ring.
Maybe it's just me, but it seems these freak incidents would   
occur more frequently years ago, than now.
I've now experienced this a couple of times with an * system  
(TDM400p  - quad FXO):
A SIP exten dials digits which are answered by a Zap trunk.  As   
soon as Zap answers, the SIP extension is connected with an   
inbound (PSTN) caller (who was expecting to hear an IVR).
My questions are:  Who's to blame (telco, tdm card, * config,  
gremlins)?  Is this avoidable?


It's called glare.
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-05 Thread Andrew Kohlsmith
On May 5, 2005 10:05 am, Ryan Courtnage wrote:
 Dial(Zap/g2...): Looks in order 1, 2, 5, 8
 Dial(Zap/G2...): Looks in order 8, 5, 2, 1
 Dial(Zap/r2...): Looks in order 8, 1, 2, 5
 Dial(Zap/R2...): Looks in order 2, 1, 8, 5

Let's just be clear.

Round Robin (r and R) will go through all the channels in order (ascend or 
decend) before reusing a channel.

group (g and G) will find the first available channel (lowest or highest).

So if you are using r, the order is always 1 2 3 4 5 6... and will not use 1 
again until all of the others have been used.

And if you are using g, the order will be the same BUT if a lower-numbered 
channel becomes free again it will be selected instead of the next numeric 
ordered channel.

e.g.
call out: uses 1
call out: uses 2
call out: uses 3
(call on 1 finishes)
call out: uses 1
call out: uses 4
call out: uses 5
(call on 4 finishes)
call out: uses 4
call out: uses 6

as you can see, it always uses the first available channel.  G is the same but 
uses the highest numbered available channel.

If you're trying to avoid glare, use g.  If you're going for even usage then 
use r.

And please, for the sake of the list, trim your responses; there is no need to 
include the ENTIRE email you're replying to.

-A.
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-04 Thread Peter Svensson
On Tue, 3 May 2005, Andrew Kohlsmith wrote:

 On May 3, 2005 02:22 pm, Ryan Courtnage wrote:
   From what I've read, glare is common in 2-way loopstart (kewlstart)
  circuits, and is impossible(?) to eliminate completely.  But now I'm
  wondering what Nortel would tell a customer who experiences glare on
  their new Meridian system... they must do something to prevent glare
  from happening.  Any ideas?
 
 Nope.
 
 Technically it shouldn't be possible with PRI but it is and does happen.  
 Typically you hunt up starting at the highest available channel, and the 
 telco hunts down which tends to keep it at bay until things get busy.

Glare is when both the net and the cpe end attempt to seize a line
simultaneously and both believe they succeeded. Glare really is impossible
on a pri as a B channel can not be requested and allocated to both parties
by mistake. The handshaking performed leaves no ambiguity as to which call
a line is allocated to.

However, a similar situation can occur when the cpe end requests a
specific B channel in a SETUP message instead of leaving the channel
selection to the net end. Unlike the glare condition this situation is
detected and the net end prevails. The cpe end should then try to allocate 
another B channel with a new SETUP message. 

Unfortunatly Asterisk as a cpe device neither lets the net end allocate
the B channel, nor does it retry using a different B channel. The problem 
is that Asterisk does not see the whole PRI as a single link with several 
channels, it sees the inidvidual channels with a common signalling path. A 
specific B channel is allocated before the signalling starts. This is a 
deficiency in Asterisk, not in isdn in general.

The solution for Asterisk is the same as for glare-prone links - hunt for
channels in the opposite direction. Note that on isdn links quite a few 
operators will by default _not_ hunt from one end or another, this has to 
be requested. The convention then is for the net end to hunt low-to-high 
and the cpe end to hunt high-to-low.

Finally, even on isdn you have end devices (phones) which may themselves 
be prone to the human equivalent of glare - picking up the handset before 
the ring is heared. Some phones allow the user to request an outside line 
by pressing a button to prevent this.

Peter


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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-04 Thread Andrew Kohlsmith
On May 4, 2005 02:54 am, Peter Svensson wrote:
 Unfortunatly Asterisk as a cpe device neither lets the net end allocate
 the B channel, nor does it retry using a different B channel. The problem
 is that Asterisk does not see the whole PRI as a single link with several
 channels, it sees the inidvidual channels with a common signalling path. A
 specific B channel is allocated before the signalling starts. This is a
 deficiency in Asterisk, not in isdn in general.

Wow, thank you for this very insightful response...  It's concise and 
describes exactly what the problem is, and why.

-A.
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-04 Thread Rich Adamson
  Everyone has probably experienced this at some point in the past:
  You pick up your analog phone.  Rather than hearing dialtone, you are
  connected with someone who has just called you.  Neither you nor them
  heard a ring.
 
  Maybe it's just me, but it seems these freak incidents would occur
  more frequently years ago, than now.
 
  I've now experienced this a couple of times with an * system (TDM400p
  - quad FXO):
  A SIP exten dials digits which are answered by a Zap trunk.  As soon
  as Zap answers, the SIP extension is connected with an inbound (PSTN)
  caller (who was expecting to hear an IVR).
 
  My questions are:  Who's to blame (telco, tdm card, * config,
  gremlins)?  Is this avoidable?
 
 
 I dont know who to blame, but we've had the same problem here with our small 
 sales team. The sales team (about once a week) will dial a call on their 
 analog phones (analog cordless phones plugged into a few SPA-2001s) - they 
 press 'talk', dial the #, then immediatly are connected to an incomming 
 call... (I use two TDM quad FXO cards to service 8 incomming lines from 
 Sprint).
 
 I havnt been able to track it down, and its not reproducable manually...

From the description, it almost sounds like glare.

With analog fxo lines, that essentially means that both asterisk and
the telco central office attempted to use the same pstn line for
outgoing and incoming lines at the same time.

Statistically, glare will occur more frequently with _small_ numbers
of pstn lines and _greater_ amounts of traffic.

I'd also guess that part of the problem might relate to how asterisk
handles call setup. In other words, when an incoming call arrives at
asterisk, asterisk probably doesn't mark the line as busy until after
the callerid arrives (and the first internal ring occurs). If an out-
going call is initiated at that time, asterisk may not know an incoming
call is just arriving. But, that's a guess for sure.

Might try using immediate=yes and usecallerid=no to see if that has
any impact. If it does, then suspect the above timing issue.


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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-04 Thread Rich Adamson
  Everyone has probably experienced this at some point in the past:
  You pick up your analog phone.  Rather than hearing dialtone, you are
  connected with someone who has just called you.  Neither you nor them
  heard a ring.
 
 I don't think this is a freak incident at all. It still happens to me with
 people I call frequently and is easily explainable. you make a call, the
 telco connects it, and before the ring generator comes into a phase of
 putting voltage on the line, they pick up the phone. The circuit was
 connected, it just never got a chance to ring, there is nothing freak
 about it, just a matter of timing.

Might also add that most central office switches do not sync the ringback
audio with the actual ringing of the pstn line. So, ringback in many
cases may be several seconds before/after the actual pstn line is ringing.
Listening for ringback will not be a valid indicator of anything just
in case someone suggests doing that.


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[Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Ryan Courtnage
Hello all,
Everyone has probably experienced this at some point in the past:
You pick up your analog phone.  Rather than hearing dialtone, you are  
connected with someone who has just called you.  Neither you nor them  
heard a ring.

Maybe it's just me, but it seems these freak incidents would occur  
more frequently years ago, than now.

I've now experienced this a couple of times with an * system (TDM400p  
- quad FXO):
A SIP exten dials digits which are answered by a Zap trunk.  As soon  
as Zap answers, the SIP extension is connected with an inbound (PSTN)  
caller (who was expecting to hear an IVR).

My questions are:  Who's to blame (telco, tdm card, * config,  
gremlins)?  Is this avoidable?

Thanks
Ryan
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Eric Wieling aka ManxPower
Ryan Courtnage wrote:
Hello all,
Everyone has probably experienced this at some point in the past:
You pick up your analog phone.  Rather than hearing dialtone, you are  
connected with someone who has just called you.  Neither you nor them  
heard a ring.

Maybe it's just me, but it seems these freak incidents would occur  
more frequently years ago, than now.

I've now experienced this a couple of times with an * system (TDM400p  - 
quad FXO):
A SIP exten dials digits which are answered by a Zap trunk.  As soon  as 
Zap answers, the SIP extension is connected with an inbound (PSTN)  
caller (who was expecting to hear an IVR).

My questions are:  Who's to blame (telco, tdm card, * config,  
gremlins)?  Is this avoidable?
It's called glare.
http://home.intekom.com/scotland/cookbook/146.htm
http://www.authorizedcom.com/lines_trunks.asp
http://www.beagle-ears.com/lars/engineer/telecom/bizphone.htm
http://www.zvon.org/tmRFC/RFC3064/Output/chapter4.html
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Josiah Bryan
On Tuesday 03 May 2005 11:40 am, Ryan Courtnage wrote:
 Hello all,

 Everyone has probably experienced this at some point in the past:
 You pick up your analog phone.  Rather than hearing dialtone, you are
 connected with someone who has just called you.  Neither you nor them
 heard a ring.

 Maybe it's just me, but it seems these freak incidents would occur
 more frequently years ago, than now.

 I've now experienced this a couple of times with an * system (TDM400p
 - quad FXO):
 A SIP exten dials digits which are answered by a Zap trunk.  As soon
 as Zap answers, the SIP extension is connected with an inbound (PSTN)
 caller (who was expecting to hear an IVR).

 My questions are:  Who's to blame (telco, tdm card, * config,
 gremlins)?  Is this avoidable?


I dont know who to blame, but we've had the same problem here with our small 
sales team. The sales team (about once a week) will dial a call on their 
analog phones (analog cordless phones plugged into a few SPA-2001s) - they 
press 'talk', dial the #, then immediatly are connected to an incomming 
call... (I use two TDM quad FXO cards to service 8 incomming lines from 
Sprint).

I havnt been able to track it down, and its not reproducable manually...

Anybody have any ideas?

-josiah

-- 
Josiah Bryan
IT Coordinator
Productive Concepts, Inc.
[EMAIL PROTECTED]
(765) 964-6009, ext. 224
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Jon Pounder

 Hello all,

 Everyone has probably experienced this at some point in the past:
 You pick up your analog phone.  Rather than hearing dialtone, you are
 connected with someone who has just called you.  Neither you nor them
 heard a ring.

I don't think this is a freak incident at all. It still happens to me with
people I call frequently and is easily explainable. you make a call, the
telco connects it, and before the ring generator comes into a phase of
putting voltage on the line, they pick up the phone. The circuit was
connected, it just never got a chance to ring, there is nothing freak
about it, just a matter of timing.

This same thing could apply to asterisk or any other pbx or telco system
since they all use the same basic arrangement of connecting circuits and
ringing them. There is no hard and fast rule I know of that says a line
must ring at least once before the called station can go off hook. Modems
and such can be programmed with this rule, but a person picking up can do
so at any random time.

An exception would be when there is more than one call path to a phone,
and effectively picking up to dial is not the same as picking up to answer
an incoming call.

Also, this could start happening more, not less as technology progresses
since something like camp-on would have higher odds of hitting this
situation since it constantly retries the number instead of the randomness
at both ends if humans are involved.



 Maybe it's just me, but it seems these freak incidents would occur
 more frequently years ago, than now.

 I've now experienced this a couple of times with an * system (TDM400p
 - quad FXO):
 A SIP exten dials digits which are answered by a Zap trunk.  As soon
 as Zap answers, the SIP extension is connected with an inbound (PSTN)
 caller (who was expecting to hear an IVR).

 My questions are:  Who's to blame (telco, tdm card, * config,
 gremlins)?  Is this avoidable?

 Thanks
 Ryan

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 !DSPAM:4277a74f32083462913418!




Jon Pounder

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Inline Internet Systems Inc.
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Tools to Power Your e-Business Solutions
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Andrew Kohlsmith
On May 3, 2005 11:40 am, Ryan Courtnage wrote:
 Everyone has probably experienced this at some point in the past:
 You pick up your analog phone.  Rather than hearing dialtone, you are
 connected with someone who has just called you.  Neither you nor them
 heard a ring.

It's not a freak accident; the switch just routed a call to you the exact 
moment that you picked up the line.  It happens.

 My questions are:  Who's to blame (telco, tdm card, * config,
 gremlins)?  Is this avoidable?

Avoidable?  Not really; it happens.  Is it really that much of a problem?  Can 
I ask why?

-A.
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RE: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Kris Boutilier

 -Original Message-
 From: Ryan Courtnage [mailto:[EMAIL PROTECTED]
 Sent: Tuesday, May 03, 2005 8:41 AM
 To: Asterisk Users Mailing List - Non-Commercial Discussion
 Subject: [Asterisk-Users] Freak incidents, who's to blame?
 
 
 Hello all,
 
 Everyone has probably experienced this at some point in the past:
 You pick up your analog phone.  Rather than hearing dialtone, 
 you are connected with someone who has just called you.  Neither you 
 nor them heard a ring.
 
{clip}
 My questions are:  Who's to blame (telco, tdm card, * config,  
 gremlins)?  Is this avoidable?

This is a condition known as 'glare' and is expected behaviour and is actually 
quite common on busy lines unless a handshaking protocol of some sort is use 
(such as wink or ground start). Essentially this handshake signals an intent to 
use the trunk before it's actually seized, thereby preventing both parties from 
seizing it simultaneously.

Google can provide far more detail.

Kris Boutilier
Information Services Coordinator
Sunshine Coast Regional District
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread John Novack
Ryan Courtnage wrote:
Hello all,
Everyone has probably experienced this at some point in the past:
You pick up your analog phone.  Rather than hearing dialtone, you are  
connected with someone who has just called you.  Neither you nor them  
heard a ring.

Maybe it's just me, but it seems these freak incidents would occur  
more frequently years ago, than now.

I've now experienced this a couple of times with an * system (TDM400p  
- quad FXO):
A SIP exten dials digits which are answered by a Zap trunk.  As soon  
as Zap answers, the SIP extension is connected with an inbound (PSTN)  
caller (who was expecting to hear an IVR).

My questions are:  Who's to blame (telco, tdm card, * config,  
gremlins)?  Is this avoidable?

Thanks
Ryan
Really no one is to blame
This is known as Glare, or a head on ( collision )
Take a basic Telephony course before attempting to become a telecom 
engineer.

Back in the good old days a PBX would have  analog trunks that were 
ground start, and tip was open when idle. The PBX would have an 
interface that knew this, and  if it found ground on the tip would move 
to the next outgoing trunk. Ground was applied to the trunk by the CO 
BEFORE it was rung. The ring signal would then  start whatever sequence 
in the PBX was necessary to answer the call.
I gather that the FXO card doesn't support a ground start trunk at all, 
being nothing more than a modem given a new lease on life.

Something other than a X100 or TDM400 is needed, and analog Ground start 
trunks from the Telco are called for for proper two way operation.
GS trunks are certainly still available in the US and probably elsewhere.
If you need enough trunks, perhaps a PRI instead?

John Novack
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Ryan Courtnage
On 3-May-05, at 10:34 AM, Eric Wieling aka ManxPower wrote:
Ryan Courtnage wrote:
Hello all,
Everyone has probably experienced this at some point in the past:
You pick up your analog phone.  Rather than hearing dialtone, you  
are  connected with someone who has just called you.  Neither you  
nor them  heard a ring.
Maybe it's just me, but it seems these freak incidents would  
occur  more frequently years ago, than now.
I've now experienced this a couple of times with an * system  
(TDM400p  - quad FXO):
A SIP exten dials digits which are answered by a Zap trunk.  As  
soon  as Zap answers, the SIP extension is connected with an  
inbound (PSTN)  caller (who was expecting to hear an IVR).
My questions are:  Who's to blame (telco, tdm card, * config,   
gremlins)?  Is this avoidable?

It's called glare.
Thank you, I'm now walking down the right path.
From what I've read, glare is common in 2-way loopstart (kewlstart)  
circuits, and is impossible(?) to eliminate completely.  But now I'm  
wondering what Nortel would tell a customer who experiences glare on  
their new Meridian system... they must do something to prevent glare  
from happening.  Any ideas?

Ryan
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RE: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Alexander Lopez


-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Eric
Wieling aka ManxPower
Sent: Tuesday, May 03, 2005 12:34 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [Asterisk-Users] Freak incidents, who's to blame?

Ryan Courtnage wrote:
 Hello all,
 
 Everyone has probably experienced this at some point in the past:
 You pick up your analog phone.  Rather than hearing dialtone, you are

 connected with someone who has just called you.  Neither you nor them

 heard a ring.
 
 Maybe it's just me, but it seems these freak incidents would occur  
 more frequently years ago, than now.
 
 I've now experienced this a couple of times with an * system (TDM400p
- 
 quad FXO):
 A SIP exten dials digits which are answered by a Zap trunk.  As soon
as 
 Zap answers, the SIP extension is connected with an inbound (PSTN)  
 caller (who was expecting to hear an IVR).
 
 My questions are:  Who's to blame (telco, tdm card, * config,  
 gremlins)?  Is this avoidable?

It's called glare.


All elaborate on 'GLARE'

Think about opening your front door on your way out just before the
person gets a chance to ring the doorbell. Bam, there you are just
GLARING at on e another.

Glare could probably be reduced if you ALWAYS walked out the back door
and those coming to visit you go to the front. You can set * to select
lines in an order opesite than the way they roll over.  For example our
lines ring in ascending order line 1, then 2, 3,4,5, etc. If you set the
PBX to grab line in decending order you will make outgoing calls on
lines 5,4,3,2,1, decreasing the chances that * will open a ZAP door and
find someone 'standing' there


Hope this helps.


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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Matt Klein
If you're going through a CLEC for your lines, they can probably set the 
Glare Preference to be You or the Telco. I'm not sure if the Baby Bells 
would add that preference option for you.

-m
On Tue, 3 May 2005, Eric Wieling aka ManxPower wrote:
Ryan Courtnage wrote:
Hello all,
Everyone has probably experienced this at some point in the past:
You pick up your analog phone.  Rather than hearing dialtone, you are 
connected with someone who has just called you.  Neither you nor them 
heard a ring.

Maybe it's just me, but it seems these freak incidents would occur  more 
frequently years ago, than now.

I've now experienced this a couple of times with an * system (TDM400p  - 
quad FXO):
A SIP exten dials digits which are answered by a Zap trunk.  As soon  as 
Zap answers, the SIP extension is connected with an inbound (PSTN)  caller 
(who was expecting to hear an IVR).

My questions are:  Who's to blame (telco, tdm card, * config,  gremlins)? 
Is this avoidable?
It's called glare.
http://home.intekom.com/scotland/cookbook/146.htm
http://www.authorizedcom.com/lines_trunks.asp
http://www.beagle-ears.com/lars/engineer/telecom/bizphone.htm
http://www.zvon.org/tmRFC/RFC3064/Output/chapter4.html
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Jon Pounder


 Really no one is to blame
 This is known as Glare, or a head on ( collision )
 Take a basic Telephony course before attempting to become a telecom
 engineer.

 Back in the good old days a PBX would have  analog trunks that were
 ground start, and tip was open when idle. The PBX would have an
 interface that knew this, and  if it found ground on the tip would move
 to the next outgoing trunk. Ground was applied to the trunk by the CO
 BEFORE it was rung. The ring signal would then  start whatever sequence
 in the PBX was necessary to answer the call.
 I gather that the FXO card doesn't support a ground start trunk at all,
 being nothing more than a modem given a new lease on life.

 Something other than a X100 or TDM400 is needed, and analog Ground start
 trunks from the Telco are called for for proper two way operation.
 GS trunks are certainly still available in the US and probably elsewhere.
 If you need enough trunks, perhaps a PRI instead?

I don't think it is even that simple to get rid of. GS trunks would take
care of the remote connect issues, but the same issue is still going to
exist on the loopstart loops to the phones themselves. if you dial a local
extension the other person can still pickup before the first ring if you
are using analog phones. All this does is move the problem with analog
trunks into a local only situation, but it still exists.






 John Novack


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Jon Pounder

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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Eric Wieling aka ManxPower
Ryan Courtnage wrote:
On 3-May-05, at 10:34 AM, Eric Wieling aka ManxPower wrote:
Ryan Courtnage wrote:
Hello all,
Everyone has probably experienced this at some point in the past:
You pick up your analog phone.  Rather than hearing dialtone, you  
are  connected with someone who has just called you.  Neither you  
nor them  heard a ring.
Maybe it's just me, but it seems these freak incidents would  
occur  more frequently years ago, than now.
I've now experienced this a couple of times with an * system  
(TDM400p  - quad FXO):
A SIP exten dials digits which are answered by a Zap trunk.  As  
soon  as Zap answers, the SIP extension is connected with an  inbound 
(PSTN)  caller (who was expecting to hear an IVR).
My questions are:  Who's to blame (telco, tdm card, * config,   
gremlins)?  Is this avoidable?

It's called glare.

Thank you, I'm now walking down the right path.
 From what I've read, glare is common in 2-way loopstart (kewlstart)  
circuits, and is impossible(?) to eliminate completely.  But now I'm  
wondering what Nortel would tell a customer who experiences glare on  
their new Meridian system... they must do something to prevent glare  
from happening.  Any ideas?
They would tell them to use groundstart or EM wink ports, and then tell 
them that the loopstart cards they bought won't work with the other 
signaling methods and have to be replaced.

--Eric
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Andrew Kohlsmith
On May 3, 2005 02:22 pm, Ryan Courtnage wrote:
  From what I've read, glare is common in 2-way loopstart (kewlstart)
 circuits, and is impossible(?) to eliminate completely.  But now I'm
 wondering what Nortel would tell a customer who experiences glare on
 their new Meridian system... they must do something to prevent glare
 from happening.  Any ideas?

Nope.

Technically it shouldn't be possible with PRI but it is and does happen.  
Typically you hunt up starting at the highest available channel, and the 
telco hunts down which tends to keep it at bay until things get busy.

-A.
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RE: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Charlie Watts
Ryan Courtnage wrote:
 On 3-May-05, at 10:34 AM, Eric Wieling aka ManxPower wrote:
 It's called glare.
 
 Thank you, I'm now walking down the right path.
 
  From what I've read, glare is common in 2-way loopstart (kewlstart)
 circuits, and is impossible(?) to eliminate completely.  But now I'm
 wondering what Nortel would tell a customer who experiences glare on
 their new Meridian system... they must do something to prevent glare
 from happening.  Any ideas?

Yup. Order your lines groundstart.
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Re: [Asterisk-Users] Freak incidents, who's to blame?

2005-05-03 Thread Henry Devito
Nortel and Toshiba and so on help eliminate this by routing outgoing calls 
starting from the highest trunk backwards and incoming calls of course start 
from the lowest trunk and work upward.
- Original Message - 
From: Ryan Courtnage [EMAIL PROTECTED]
To: Asterisk Users Mailing List - Non-Commercial Discussion 
asterisk-users@lists.digium.com
Sent: Tuesday, May 03, 2005 1:22 PM
Subject: Re: [Asterisk-Users] Freak incidents, who's to blame?


On 3-May-05, at 10:34 AM, Eric Wieling aka ManxPower wrote:
Ryan Courtnage wrote:
Hello all,
Everyone has probably experienced this at some point in the past:
You pick up your analog phone.  Rather than hearing dialtone, you  are 
connected with someone who has just called you.  Neither you  nor them 
heard a ring.
Maybe it's just me, but it seems these freak incidents would  occur 
more frequently years ago, than now.
I've now experienced this a couple of times with an * system 
(TDM400p  - quad FXO):
A SIP exten dials digits which are answered by a Zap trunk.  As  soon 
as Zap answers, the SIP extension is connected with an  inbound (PSTN) 
caller (who was expecting to hear an IVR).
My questions are:  Who's to blame (telco, tdm card, * config, 
gremlins)?  Is this avoidable?

It's called glare.
Thank you, I'm now walking down the right path.
From what I've read, glare is common in 2-way loopstart (kewlstart) 
circuits, and is impossible(?) to eliminate completely.  But now I'm 
wondering what Nortel would tell a customer who experiences glare on 
their new Meridian system... they must do something to prevent glare  from 
happening.  Any ideas?

Ryan
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