VoIPowering Your Office: Connect SipX to Analog Phone Lines

by Carla Schroder

. . . plus tweaking dialplans, setting up prompts and voicemail accounts—generally attending to those myriad phone-system details.

Connecting your SipX server to your analog phones lines requires using a suitable FXO gateway, such as the AudioCodes AUD-MP-114-FXO. There are many of these to choose from; I picked this one at random to use as an example. This is a four-port analog media gateway that includes a lot of nice features, such as fax and modem, voice compression, jitter buffer, echo canceller, and PSTN fallback for 911. This is a typical feature set for VoIP gateways; they tend to pack in a lot of goodies.

Basic setups
You'll be doing a bit of skipping around in the SipX Web configuration interface as you set up your system. Set things up in this order:

  • Media gateway
  • SIP phones
  • User accounts and groups
  • Dialplan
  • Custom prompts
This should get you up and running with a minimum of confusion. Last week we took a configure-phones-and-users-tour, so this week we'll cover the rest.

Media gateway
Suppose you have four analog phone lines. You need to enter these on the gateway itself—and the extensions they need to be routed to. Then set up a dialplan in SipX to handle the incoming calls the way you want. Go to the SipX Web administration panel at Devices -> Gateways to setup a new media gateway. You need the device's MAC address, IP address, and the address of your primary DNS server. Then you'll use the gateway's own configuration tools for further tweaks, if they are needed. For example, AudioCodes devices have Web configuration interfaces.

Some day SipX will have full plug-and-play support for media gateways. This means the SipX Configuration Server will create a profile that the gateway will download every time it starts up. Until that day comes, it has to be configured manually.

Configuring dialplans in SipX is pretty easy. Go to the System -> Dialplans page and take a look around. First click on the Permissions link to see some interesting options. There are a number of interesting defaults: 900 dialing is disabled, external forwarding is disabled, and recording system prompts is disabled. Long distance, international, and other types of dialing are enabled. You can't make changes on this page, because they are set on an as-needed basis on the Users and User Groups pages.

Next, go back to System -> Dialplans. Only AutoAttendant and Internal are enabled; Local, Long Distance, Emergency, and all the other built-in dialplans are disabled by default.

AutoAttendant has a number of useful built-in options. You get two pre-fab auto-attendants, Operator and After Hours. It's easy to set these up for business, evenings, weekends, and holidays just by clicking check-boxes, and entering your business hours and holiday schedule. The default extension is 100, which is easy to change if you want to use something else.

What if you don't like the prefab auto-attendants, or want to review their settings? Go to Features -> Auto Attendants. You'll see their existing settings, and can listen to their current greetings. The default greeting says "Welcome to Pingtel communications", which is probably not what you want it to say. To change it, add a real user who is already set up with a phone and voicemail to the Administrators group. Do this by clicking the Users tab, select a user, then click "Show Advanced Settings," then type "administrators" on the Groups line. Now this user can make a new Auto Attendant prompt by logging into her own voicemail, selecting option 7, then option 2, then 1.

Custom prompts
To edit the Standard, After Hours, or Special Occasion greetings, log into voicemail, then select options 7 and then 1, then follow the prompts. What if you want to create brand-new prompts? Try Audacity, which is a very nice sound-recording and editing studio. It runs on all the major operating systems, is free of cost, and is open source. When you record your custom prompts, use 8kHz sampling, mono, 16 bits. Save them as .wav files. You can use a separate PC on your network for recording new prompts, then copy the new sound files to your SipX server. Put them in /usr/share/www/doc/stdprompts. Then to use new custom prompts for your Auto Attendants, for one example, open the Features -> Auto Attendants page, then select new sound files from there using the Browse button.

Users can adjust their own voicemail settings by pointing their Web browsers to http://[sipx server name or ip], then clicking Voicemail. To log in, they need their SipX username, which is the phone extension, and their PINs. This page is for selecting greetings, viewing inboxes, adding custom folders, and configuring notifications. To change greetings they need to log in to voicemail from their phones, then follow the prompts for managing their own greetings.

You'll want to allocate a lot of disk space for voicemail, because it uses the .wav file format. .wav files are good-quality and playable on Linux, Mac OSX, and Windows, but they are large because they are uncompressed.

VoIPowering Your Office: Meet SipX, the SIP iPBX Server for Linux
VoIPowering Your Office: Installing SipX
VoIPowering Your Office: Recovering SipX Passwords and DNS Done Right
VoIPowering Your Office: SipX and IP Phones

This article was originally published on Monday Mar 12th 2007