Blog Archive - VoIP

Running Asterisk with SELinux I'm not fully certain how much SELinux improves security, but I get paid by the hour, so it does improve my paycheque.Read more...

Configuring Asterisk 20 to Store PJSIP Endpoints in a Realtime Database This article describes the configuration files necessary to alter in order to configure Asterisk 20 to store PJSIP endpoints in a database.Read more...

Convert audio files to ulaw or sln for use with a VoIP PBX (Updates for 2018) Converting high quality audio files to ulaw is easy, but making them sound good takes some effort. Keep reading for the technique we use, updated for 2018.Read more...

Mango's Guide to Configuring an OBi100, OBi110, OBi202, OBi200, OBi302, and OBi300 ATA We used Linksys ATAs for many years but upgraded to Obihai when we needed a device with an FXO port. Obihai has outdone themselves and created some devices that are even more configurable than their older PAP2T, SPA2102, and SPA3102. OBi ATAs are deficient in only a few ways - for example a mediocre jitter buffer, and no way of routing calls based on Caller ID Name or customizing Caller ID Name. Fortunately, OBi ATAs' good qualities - particularly their excellent audio and powerful call routing - far exceed their shortcomings and they are what we believe to be the finest ATAs available today.Read more...

Setting up QoS for VoIP on Tomato routers A question we're asked often is, "Why do I need QoS?" If your VoIP calls already sound every bit as good (or better) than a POTS call, and you never have dropouts or distorted audio, then you don't need QoS. On the other hand, if you're a heavy or even moderate user of your internet connection, and you aren't lucky enough to have more bandwidth than you can ever use, it is our opinion that QoS is essential.Read more...

Tests of Asterisk Proxying Audio Yesterday, we wrote an article about how to remove Asterisk from the media path if NAT was involved. Today's article focuses on why you would want to do such a thing. The answer depends on the specifications of your project. If your project requires Asterisk to listen for DTMF, record the call, transcode between codecs, or any other feature that involves audio processing, Asterisk will need to proxy the audio. If that doesn't apply, here are some reasons why you might not want Asterisk to handle the audio:Read more...

Asterisk directmedia and NAT Recently we were vehemently told it is impossible to remove Asterisk from the media path if there is NAT involved. Naturally, we had to find out if that was wrong. It is absolutely possible, and here are a few ways to do it. These observations are based on experiments with Asterisk 11.Read more...

Has your router set up secret port forwards without your knowledge? I admit the title may be a little bit sensational. Please forgive me and read this anyway. For the tl;dr, scroll down to the link to the STUN Test Utility.Read more...

Use POTS for all outbound calls on an OBi110 A user recently stated that they wanted all outbound calls to be passed directly to their POTS line, with no interaction from the OBi110. Here is one way you can configure an OBi110 to present the user with a POTS dial tone:Read more...

OBi110: How to use POTS if VoIP or internet is down Many users of the OBi110 route local calls via POTS, and use VoIP for long distance. But what if your internet service is not working, or your VoIP provider's equipment is down? Fortunately, the OBi110's Trunk Groups feature will allow you to configure the OBi110 to try different routes in a priority fashion. For this example, let's assume our VoIP provider is configured on sp1. This technique may be used with any combination of service providers or the LINE Port.Read more...

Blocking Telemarketers with an OBi ATA No one likes telemarketers, but if you have an OBi ATA, you can easily blacklist them based on their Caller ID. For this we'll use the ATA's excellent User Defined Digit Maps feature.Read more...

Using an OBi ATA as an FXO port or Google Voice trunk for Asterisk or your IP Phone If you need an FXO card for your IP PBX, expect to pay hundreds of dollars for a good one. But what if your PBX doesn't have expansion slots, or is in a different location from your POTS line, or your project is for home/small office use and you require a device that works just as well for a fraction of the price? You're sure to be delighted with an OBi110. If you wish to add Google Voice to your call routing, any OBi ATA will be more than up to the challenge.Read more...

Using VoIP for POTS Voicemail with an OBi110 Those of you who mix VoIP and POTS may find it useful to use VoIP-based voicemail when you're unable to answer your POTS calls. There are a few reasons you might want to do this. VoIP voicemail is typically free, but POTS providers often charge for it. VoIP voicemail often has more/better features, such as email or SMS notification, or even multiple voicemail boxes for different people. Also, it might be convenient to have one single mailbox to check instead of having to check both a POTS mailbox and a VoIP mailbox.Read more...

VoIP Security - Could Someone be Listening In? The question of VoIP security often comes up on various VoIP forums, and it's a good one. Could someone be listening to your conversation? While it's theoretically possible, here are a few security tips that will help keep your network secure. The first thing we'd like to point out is that VoIP can actually be much easier to secure than traditional telephone service!Read more...

ATAs vs. IP Phones: Which should you choose? Instead of using a customary ATA to convert legacy telephones or PBX equipment, some users of VoIP prefer to use a "pure IP" system and use IP phones. There are advantages to both methods.Read more...

Configure your Linksys VoIP ATA the right way! ATAs made by Linksys (formerly Sipura) are arguably the most popular ATAs amongst consumers and small businesses, because of their wide array of configuration options. However, their default settings are not appropriate for users in Canada and the USA. Let's talk about some settings you can use to ensure that your VoIP equipment properly matches your region. We apologize in advance for Mango's verbosity but truly feel that the information in this article is very important. If you're in a hurry, read the bold parts, and the last three paragraphs labeled important note.Read more...

Linksys Dial Plan Tips and Tricks One of the most common questions we get asked about VoIP is, "Is it still okay if I dial 10 digits for local calls?" Regardless of the fact that that's a terrible first question to ask, the answer is up to you. The dial plan on Linksys devices is one of their most powerful features, and with it, you can configure your dialing rules any way you want.Read more...