[asterisk-users] Snom phones, blinking lights and call pickup

Philipp von Klitzing klitzing at pool.informatik.rwth-aachen.de
Wed Nov 28 07:10:46 CST 2007


> > 1. Use group dial like in Dial(SIP/1&SIP/2) and have your monitor phones 
> > each act as SIP/2 to SIP/6 with dedicated (!) lines that have their 
> > ringer set to "silent". You might want to adjust the Caller ID name to 
> > prefix it with the called number like "to 123: from 4567890". The SNOMs 
> > have 12 lines, so why not actually use some of them ...
> I wouldn't like that personally but it's an interesting idea anyway. 

It works, but there are a few downsides to it:

* from an administrators point of view this can quickly result in quite 
some setup work if we are talking - say - 3 main phones and 15 monitor 
phones that are supposed to monitor _each_ of the 3 main phones. But ok, 
you do that only once.

* there are rare occasions where a user on a monitor phones wants to 
place a new call and picks up the handset in the very moment a new 
monitor calls starts silently ringing --> user answers the call without 
wanting to/being aware of that. This can, however, be avoided by training 
the user to always press a free line button for a new call.

* the behaviour of group dialing needs to be observed carefully: Should 
one of the phones SIP/2 to SIP/6 be put on DND (or permanent forward) 
then the entire call will fail right away, meaning that SIP/1 will not 
even ring once. The admin will need to either disable DND & redirection, 
or introduce a more advanced DND handling like illustrated on

> > A variation of this: Record a new ringer sound that is a) long and b) has 
> > 10+ seconds silence at the beginning, and let the monitoring SNOMs use 
> > that.
> Better use the ring_after_delay setting if you plan to go
> this way.
> http://wiki.snom.com/Web_Interface/Settings/Common#ring_after_delay

Indeed that is a smarter method. :-)

> > 3. Stay with your current solution, and add a SIP MESSAGE sent using 
> > sipsak using System() that informs the monitoring phones of the caller 
> > ID; I haven't tested this particular case so I am not sure if this SIP 
> > MESSAGE would not be immediately overwritten on the phone's display with 
> > other data like (useless) pick-up information.
> Might work but it smells like an ugly hack. Remember you need to clear
> the desktop messages. 

Using sipsak is not a hack it all: Especially on a SNOM 360 with their 
large screens this allows for nice informations screens (voicemail 
options helper or route information in case of a least cost router 

BTW, you can clear a SIP desktop message thru another new incoming call - 
now *that* I would consider a hack, but if you place that call to a 
silent ringer line that is also set to auto-answer (and has "record 
missed calls" to off) you have solved the issue. ;->

Cheers, Philipp

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