Panoramisk / The VoIP druid 

On peut être passionné par la téléphonie et prendre soin de soi : "Faites du sport, faites du vélo" est la devise du site d'e-commerce lancé par l'un des auteurs de Panoramisk : bikeo. Si vous faites du vélo, que ce soit en ville, sur la route ou sur les chemins plus accidentés, n'hésitez pas à aller faire un petit tour sur www.bikeo.fr pour vos prochains achats verts.
En plus leur plate-forme de téléphonie utilise Asterisk, comme quoi on peut la convergence est une réalité.

Phone line supervision is one of the great and mandatory tools for any enterprise telephony product. Asterisk is proposing this feature based on the SIP protocol tools but each phone (or softphone) is implementing it through a proprietary approach. In addition to the supervision the line pickup tool is important and sometimes not easy to configure.

It is generally simple to supervise a phone line with the SIP toolkit, but in order to pickup the line an interaction with the PBX is required: by hitting the button near the supervised line a call should be placed with a specific prefix. The Aastra 53i phone¹ is implementing this feature really easily and targeting the Asterisk solution. This article shows how simple it is to configure.

Line supervision

We have made our lab test with an Aastra 53i model (the small one) and a release 1.4.8 of Asterisk. This phone doesn’t have dedicated supervision line, but we can use up to 4 of the 6 available programmable lines located on the upper part of the phone. 4 supervised lines would be enough for a small user group, if more are required, the other models of the 5i portfolio can be used and expanded with specific expansion modules. We have already talked about the line supervision in our article “Asterisk and line supervision”, we will not talk here about Asterisk configuration for this feature.

On the phone itself, we need to associate the key and the line to supervised. Using the web interface, in the menu Operation/Programmable Keys we have to specify the following fields:

• Type: BLF
• Value: ligne number (like in the hint specification of the extensions.conf file)
• Line: index of the SIP line on the phone, this refers to the Asterisk server

The LED near the programmed key will blink when the line is ringing and be on when the line is in use. Simple and straightforward.

Line pickup

The next step after supervision is line pickup. For this feature to work on any phone, we need at the Asterisk level to specify to which group the line is belonging. In the sip.conf file, we need to set the Pickupgroup parameter for each line. The numerical value associated is the group identifier. In addition, we need an extension prefix for the “directed pickup” function. In the extensions.conf file, we set a prefix with the Pickup() application command:

exten => _916.,1,Pickup(${EXTEN:3})

In this example, we can pickup a specific line (when this one is ringing) by dialing its number prefixed by the 916.

At the Aastra 53i level, we need to enable the “Directed Pickup” feature in the Basic Settings->Preferences menu and specify the pickup prefix configured in the Asterisk, here the 916².

Conclusion

With this very simple approach of configuring both supervision and line pickup we have reached a similar feature level on IP telephony that we have previously on specific PBX traditional systems. This kind of development will for sure allow an easy migration towards IP telephony without changing too much users habit. Even if Aastra is not the only vendor to propose this feature, we have liked the eased integration with Asterisk, which from a vendor of IP PBX is a real good point.

1. and the whole 5i product line: 55i and 57i [↩]
2. this should be changed to match your dialling plan [↩]