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Happy New Year: It’s Incredible PBX 2027 for the Raspberry Pi

Ever since Eben and Liz Upton first introduced the Raspberry Pi to our Charleston community over a decade ago, the primary focus of their development team has been to encourage people of the world to learn about computers on an affordable platform. To this day, the Raspberry Pi 4B can still be purchased (if you can find one) for $35. Unfortunately, supply chain issues have taken their toll. If you prefer not to pay a premium for the Raspberry Pi 4B or 400 keyboard, then visit the RPiLocator. If time is of the essence, then eBay is your friend for both the RasPi4 and the RasPi 400 keyboard.

Many of you may know that Mark Spencer, who founded Digium and initially developed Asterisk®, now has a new avionics company in Huntsville, Avilution. You may be surprised to learn that their unPanel Avionics platform was developed using redundant Raspberry Pi’s.

UPDATE: Download the latest Incredible PBX 2027 image for RasPi here.

To celebrate the New Year, we’ve taken an entirely new approach in developing this latest Incredible PBX iteration for the Raspberry Pi. In previous builds, we’ve offered a turnkey image for the Raspberry Pi. This time around we’ve incorporated the same Debian 11 installer that we use on AMD64 and ARM64 platforms. The primary advantage is that this installer will continue to work with future Raspberry Pi hardware that supports the Debian 11 platform. It also allows us to make slipstream enhancements across all hardware platforms in minutes instead of weeks. One final benefit of the new design is that you now can take advantage of the Raspberry Pi Imager which lets you create the base Debian 11 microSD platform for the Raspberry Pi in minutes.

What’s Included? Incredible PBX 2027 serves up a never before available VoIP powerhouse featuring Asterisk 20 and all FreePBX 16 GPL modules, an Apache web server, the latest MariaDB SQL server (formerly MySQL), SendMail mail server, Webmin, and most of the Incredible PBX feature set including SIP, PJSIP, SMS, voice recognition, AsteriDex, gTTS Text-to-Speech VoIP applications, Call-By-Name Dialing, News, Weather, Telephone Reminders, and hundreds of features that typically are found in commercial PBXs: Conferencing, IVRs and Email Delivery of transcribed voicemails, AutoAttendants, Voicemail Blasting, and more. We’ve also incorporated the Zero Trunk Configuration feature from the LITE build which lets you sign up with one of our VoIP providers and start making and receiving calls instantly. Or you can use the new ClearlyIP trunking module included in the GUI for seamless integration of SMS messaging into FreePBX® and its User Control Panel.

Choosing a SIP Provider. As we mentioned, Incredible PBX 2027 comes preconfigured to support many of the major SIP providers including those that financially support Nerd Vittles and our open source projects: ClearlyIP, Skyetel, and VoIP.ms. As the old saying goes, they may not be the cheapest, but you get what you pay for. With all our providers, you only pay for minutes you use so signing up with more than one provider is a smart idea. For the full list of supported VoIP providers, visit the Incredible PBX Wiki.

Assembling the Required Raspberry Pi Components

Before you can deploy Incredible PBX 2027, you’ll first need the necessary Raspberry Pi hardware. To support the enhanced Incredible PBX 2027 platform, we strongly recommend either the Raspberry Pi 400 or the Raspberry Pi 4B with at least 2GB RAM. You can choose a reseller below for quicker delivery. Assuming you already own an HDMI-compatible monitor and a USB keyboard (only required if you don’t buy a RasPi 400)…

  • Raspberry Pi 4B or Raspberry Pi 400
  • $10 USB-C RasPi 4 (only) Power Supply
  • $9 32GB microSDHC Class 10 card (strongly recommended!)
  • $5 Official RasPi 4B Case or see above for our favorite
  • Getting Started with Incredible PBX 2027

    Begin by downloading Raspberry Pi Imager for PC, MAC, or Ubuntu desktop. Run the Imager from your desktop computer with the following settings after inserting microSD card in your desktop machine:

    OS: Raspberry Pi OS (other) -> Raspberry Pi OS Lite (64-bit)
    Storage: Select your microSD card (32GB Type 10 recommended)
    Click WRITE

    Remove the microSD card from your desktop computer. Insert it into your Raspberry Pi and power on the device. The initial Raspberry Pi OS setup for the United States follows. For users elsewhere, follow your nose.

    Choose keyboard layout: (Other, English (US) for USA users)
    Keyboard Layout: English (US)
    username: nerd
    password: make it secure, type it twice
    login: nerd with new password
    sudo passwd root
    create new secure root password
    logout: exit
    login: root with new root password
    userdel nerd
    nano -w /etc/ssh/sshd_config
      edit and uncomment: PermitRootLogin yes
      uncomment PasswordAuthentication yes
      save: Ctrl-X, Y, then ENTER key
    run: raspi-config
      Settings Apply to: pi
      Localization: WLAN Country: US
      System Options: Wireless LAN: Enter your SSID and SSID passphrase
      System Options: Hostname: debian
      System Options: Power LED: YES
      Interface Options: SSH: YES
      Localization: Locale: Disable en_GB.UTF-8 and Enable en_US.UTF-8
      Localization: TimeZone: America, NewYork
      FINISH and Reboot

    Once your Raspberry Pi has restarted, login as root with your root password and issue the following commands:

    wget http://incrediblepbx.com/IncrediblePBX2027-D-RasPi.sh
    chmod +x IncrediblePBX2027-D-RasPi.sh
    ip a

    To assure that your desktop computer is whitelisted in the Incredible PBX firewall, we recommend completing the rest of the install using SSH or Putty on your desktop machine. The ip a command above will tell you the local IP address of your RasPi. So login using this command: ssh root@ip-address. Then issue the following command:


    When the install finishes, reboot your Raspberry Pi and log back in as root. Let the Automatic Update Utility bring your system up to current specs after which the pbxstatus display should show something like the following.

    NOTE: To activate an OpenVPN client connection, create and copy a client configuration named incrediblepbx2027.ovpn from your OpenVPN server into the /etc folder & reboot.

    First Boot of Incredible PBX 2027

    If you entered WiFi credentials when running raspi-config above and your Raspberry Pi does not have a wired network connection, it should automatically enable the Wi-Fi connection on reboot. Issuing the command ip a will tell you the local IP addresses of wlan0 and eth0. With the Raspberry Pi 3B, 4B and 400, WiFi is built into the hardware. But you still have to provide your SSID name and SSID password to make a connection to your WiFi network. If pbxstatus does not show a network connection, here’s how to enable Wi-Fi:

    If your WiFi network requires a password, insert the following into /etc/wpa_supplicant/wpa_supplicant.conf:

    ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev


    Now restart your server: reboot. When the reboot finishes, you now should have network connectivity.

    You may also need to change the default PortKnocker setting to your wireless LAN connection:

    sed -i 's|eth0|wlan0|' /etc/default/knockd
    service knockd restart


    Finally, if your PBX is sitting behind a NAT-based router, you’ll need to redirect incoming UDP 5060-5061 and UDP 10000-20000 traffic to the private IP address of your RasPi. This is required for all of the SIP providers included in the Incredible PBX 2027 build. Otherwise, all inbound calls will fail.

    Configuring Skyetel for Incredible PBX 2027

    If you’ve decided to go with Skyetel, here’s the drill. Sign up for Skyetel service and take advantage of the Nerd Vittles Free $10 credit and BOGO special. First, complete the Prequalification Form here. You then will be provided a link to the Skyetel site to complete your registration. Once you have registered on the Skyetel site and your account has been activated, open a support ticket and request the $10 credit for your account by referencing the Nerd Vittles special offer. Once you are happy with the service, open another ticket after funding your account and request that Skyetel match your deposit of up to $250. That gets you up to $500 of helf-price calling. Credit is limited to one per person/company/address/location. If you have numbers to port in, you can do it at no cost after funding your account. Effective 10/1/2023, $25/month minimum spend required.

    Skyetel typically does not require SIP registrations to make connections to your PBX. Instead, Skyetel utilizes Endpoint Groups to identify which servers can communicate with the Skyetel service. An Endpoint Group consists of a Name, an IP address, a UDP or TCP port for the connection, and a numerical Priority for the group. For incoming calls destined to your PBX, DIDs are associated with an Endpoint Group to route the calls to your PBX. For outgoing calls from your PBX, a matching Endpoint Group is required to authorize outbound calls through the Skyetel network. Thus, the first step in configuring the Skyetel side for use with your PBX is to set up an Endpoint Group. Here’s a typical setup for Incredible PBX 2027:

    • Name: MyPBX
    • Priority: 1
    • IP Address: PBX-Public-IP-Address
    • Port: 5061
    • Protocol: UDP
    • Description: 2027.incrediblepbx.com

    To receive incoming PSTN calls, you’ll need at least one DID. On the Skyetel site, you acquire DIDs under the Phone Numbers tab. You have the option of Porting in Existing Numbers (free for the first 60 days after you fund your account) or purchasing new ones under the Buy Phone Numbers menu option.

    Once you have acquired one or more DIDs, navigate to the Local Numbers or Toll Free Numbers tab and specify the desired SIP Format and Endpoint Group for each DID. Add SMS/MMS and E911 support, if desired. Call Forwarding and Failover are also supported. That completes the VoIP setup on the Skyetel side. System Status is always available here.

    Configuring VoIP.ms for Incredible PBX 2027

    To sign up for VoIP.ms service, may we suggest you use our signup link so that Nerd Vittles gets a referral credit for your signup. Once your account is set up, you’ll need to set up a SIP SubAccount and, for Authentication Type, choose Static IP Authentication and enter your Incredible PBX 2027 server’s public IP address. For Transport, choose UDP. For Device Type, choose Asterisk, IP PBX, Gateway or VoIP Switch. Order a DID in their web panel, and then point the DID to the SubAccount you just created. Be sure to specify atlanta1.voip.ms as the POP from which to receive incoming calls. On the Incredible PBX side, simply Enable the VoIPms trunk and save your update.

    Adding a Bootable SSD to Raspberry Pi

    Shown below are the two components that make up the 256GB storage solution for the Raspberry Pi. These include the M.2 SSD SATA drive and the M.2 enclosure which provides a USB connector that’s compatible with your RasPi. Assembly of the components takes less than a minute as shown in the steps below:

    You can order the M.2 SSD SATA drive and the M.2 enclosure using our Amazon referral links which help support Nerd Vittles and the Incredible PBX open source project.

    Once you have assembled your SSD in the sleeve, log back in as root using SSH or Putty. For best performance, insert the SSD drive into one of the blue USB 3.0 ports and verify that /dev/sda device is shown when you issue the command: fdisk -l

    Now proceed with the following steps to copy the image from your microSD card to the new SSD SATA drive:

    rpi-clone -l -e sda -f sda
    # answer prompts with yes and incred2027
    # once the image is copied, dismount the drive when prompted
    mount /dev/sda2 /mnt/clone
    cd /mnt/clone/boot
    cp -p -r /boot/* .
    sed -i 's|sda2|mmcblk0p2|' /boot/cmdline.txt
    cd /
    umount /mnt/clone

    Now you’re ready to restart your Raspberry Pi from the SSD SATA drive. Remove the microSD card and reboot your server.

    Configuring a Softphone for Incredible PBX 2027

    We’re in the home stretch now. You can connect virtually any kind of telephone to your new PBX. Plain Old Phones require an analog telephone adapter (ATA) which can be a separate board in your computer from a company such as Digium. SIP phones can be connected directly so long as they have an IP address. These could be hardware devices or software devices such as the YateClient softphone. We’ll start with a free one today so you can begin making calls. You can find dozens of recommendations for hardware-based SIP phones both on Nerd Vittles and the PIAF Forum when you’re ready to get serious about VoIP telephony.

    We recommend YateClient which is free. Download it from here or the Mac App Store. Run YateClient once you’ve installed it and enter the credentials for the 701 extension on Incredible PBX. You can find them by running /root/show-passwords. You’ll need the IP address of your server plus your extension 701 password. In the YateClient, fill in the blanks using the IP address of your Server, 701 for your Username, and whatever Password was assigned to the extension when you installed Incredible PBX. Click OK to save your entries.

    Once you are registered to extension 701, close the Account window. Then click on YATE’s Telephony Tab and place some test calls to the numerous apps that are preconfigured on Incredible PBX. Dial a few of these to get started:

    DEMO - Apps Demo
    123 - Reminders
    947 - Weather by ZIP Code
    951 - Yahoo News
    TODAY - Today in History
    LENNY - The Telemarketer's Worst Nightmare

    If you are a Mac user, another great no-frills softphone is Telephone. Just download and install it from the Mac App Store.

    Last but not least, we also like the Zoiper5 free softphone. You can download it for your Windows, Mac, and Linux desktops here.

    Audio Issues with Incredible PBX 2027

    If you experience one-way or no audio on some calls, add your external IP address and LAN subnet in the GUI by navigating to Settings -> Asterisk SIP Settings. In the NAT Settings section, click Detect Network Settings. Click Submit and Apply Settings to save your changes.

    Configuring Gmail as Smart Relay Host

    Most Raspberry Pi implementations will be on networks managed by companies like Comcast, Spectrum, and AT&T that block downstream mail servers (that’s you) from sending email. The solution is to use Gmail or your local ISP as a smart relay host to send mail from your server. You’ll need this to deliver voicemails via email. Here’s how to set it up using a Gmail account. IMPORTANT: You MUST use a Gmail App Password instead of your Gmail account password.


    Now send yourself a test email message to make sure things are working properly:

    echo "test" | mail -s testmessage yourname@yourmailprovider.com

    Incredible PBX 2027 Administration

    We’ve eased the pain of administering your new PBX with a collection of scripts which you will find in the /root folder after logging in with SSH or Putty. Here’s a quick summary of what each of the scripts does.

    admin-pw-change lets you update the admin password for web browser access to the Incredible PBX GUI.

    apache-pw-change lets you update the admin password for Apache applications such as AsteriDex and Reminders.

    add-fqdn is used to whitelist a fully-qualified domain name in the firewall. Because Incredible PBX 2027 blocks all traffic from IP addresses that are not whitelisted, this is what you use to authorize an external user for your PBX. The advantage of an FQDN is that you can use a dynamic DNS service to automatically update the IP address associated with an FQDN so that you never lose connectivity.

    add-ip is used to whitelist a public IP address in the firewall. See the add-fqdn explanation as to why this matters.

    del-acct is used to remove an IP address or FQDN from the firewall’s whitelist.

    iptables-restart is the ONLY command you should ever use to restart the IPtables firewall and Fail2Ban.

    knock.FAQ contains your PortKnocker credentials for emergency access to your server if the firewall locks you out. Tutorial here.

    reset-conference-pins is a script that automatically and randomly resets the user and admin pins for access to the preconfigured conferencing application. Dial C-O-N-F from any registered SIP phone to connect to the conference.

    reset-extension-passwords is a script that automatically and randomly resets ALL of the SIP passwords for extensions 701-705. Be careful using this one, or you may disable existing registered phones and cause Fail2Ban to blacklist the IP addresses of those users. HINT: You can place a call to the Ring Group associated with all five extensions by dialing 777.

    reset-reminders-pin is a script that automatically and randomly resets the pin required to access the Telephone Reminders application by dialing 123. It’s important to protect this application because a nefarious user could set up a reminder to call a number anywhere in the world assuming your SIP provider’s account was configured to allow such calls.

    rpi-clone is a utility that makes it easy to make a bootable image of the microSD card used to start your Raspberry Pi. You’ll need a USB-to-microSD adapter to begin. Insert a backup microSD card large enough to hold all of the data on the primary microSD card (df -h). Insert the USB stick with the card. Identify the backup microSD card, usually sda (fdisk -l). Format the backup microSD card: mkfs.vfat /dev/sda1 && mkfs.ext4 /dev/sda2. Then issue the following command to clone the primary microSD card: rpi-clone -f sda. Tutorial here.

    show-feature-codes is a cheat sheet for all of the feature codes which can be dialed from any registered SIP phone. It documents how powerful a platform Incredible PBX 2027 actually is. A similar listing is available in the GUI at Admin -> Feature Codes.

    show-passwords is a script that displays ALL of the passwords associated with Incredible PBX 2027. This includes SIP extension passwords, voicemail pins, conference pins, telephone reminders pin, and your Anveo Direct outbound calling pin (if configured). Note that voicemail pins are configured by the user of a SIP extension the first time the user accesses the voicemail system by dialing *97.

    timezone-setup lets you reconfigure the correct time zone for your server.

    purge-cdr-cel-records cleans out all existing entries in both the CDR and CEL tables of the Asterisk CDR database.

    sig-fix disables module signature checking in FreePBX. It is automatically disabled upon installation.

    update-IncrediblePBX is the Automatic Update Utility which checks for server updates from incrediblepbx.com every time you log into your server as root using SSH or Putty. Do NOT disable it as it is used to load important fixes and security updates when necessary. We recommend logging into your server at least once a week.

    pbxstatus (shown above) displays status of all major components of Incredible PBX 2027.

    Forwarding Calls to Your Cellphone. Keep in mind that inbound calls to your DIDs automatically ring all five SIP extensions, 701-705. The easiest way to also ring your cellphone is to set one of these five extensions to forward incoming calls to your cellphone. After logging into your PBX as root, issue the following command to forward calls from extension 705 to your cellphone: asterisk -rx "database put CF 705 6781234567"

    To remove call forwarding: asterisk -rx "database del CF 705"

    Keeping FreePBX 16 Modules Current

    We strongly recommend that you periodically update all of your FreePBX modules to eliminate bugs and to reduce security vulnerabilities. Make a backup image with rpi-clone first! From the Linux CLI, log into your server as root and issue the following commands:

    rm -f /tmp/*
    fwconsole ma upgradeall
    fwconsole reload
    systemctl restart apache2

    Resolving an Expired Certificate Alert

    1. Navigate to Admin -> Certificate Management in the FreePBX GUI
    2. Click the Trashcan to delete the Self-Signed Certificate
    3. Click New Certificate -> Generate Self-Signed Certificate
    4. In the Description field, type: Default
    5. Click Generate Certificate button

    What About Fax Support?

    Come back next week for a pleasant surprise.

    Continue Reading: Icing on the Cake for Incredible PBX but do NOT deploy Exim.

    Originally published: Monday, January 23, 2023

    Need help with Asterisk? Visit the VoIP-info Forum.


    Special Thanks to Our Generous Sponsors

    FULL DISCLOSURE: ClearlyIP, Skyetel, Vitelity, DigitalOcean, Vultr, VoIP.ms, 3CX, Sangoma, TelecomsXchange and VitalPBX have provided financial support to Nerd Vittles and our open source projects through advertising, referral revenue, and/or merchandise. As an Amazon Associate and Best Buy Affiliate, we also earn from qualifying purchases. We’ve chosen these providers not the other way around. Our decisions are based upon their corporate reputation and the quality of their offerings and pricing. Our recommendations regarding technology are reached without regard to financial compensation except in situations in which comparable products at comparable pricing are available from multiple sources. In this limited case, we support our sponsors because our sponsors support us.

    BOGO Bonaza: Enjoy state-of-the-art VoIP service with a $10 credit and half-price SIP service on up to $500 of Skyetel trunking with free number porting when you fund your Skyetel account. No limits on number of simultaneous calls. Quadruple data center redundancy. $25 monthly minimum spend required. Tutorial and sign up details are here.

    The lynchpin of Incredible PBX 2020 and beyond is ClearlyIP components which bring management of FreePBX modules and SIP phone integration to a level never before available with any other Asterisk distribution. And now you can configure and reconfigure your new Incredible PBX phones from the convenience of the Incredible PBX GUI.

    VitalPBX is perhaps the fastest-growing PBX offering based upon Asterisk with an installed presence in more than 100 countries worldwide. VitalPBX has generously provided a customized White Label version of Incredible PBX tailored for use with all Incredible PBX and VitalPBX custom applications. Follow this link for a free test drive!

    Special Thanks to Vitelity. Vitelity is now Voyant Communications and has halted new registrations for the time being. Our special thanks to Vitelity for their unwavering financial support over many years and to the many Nerd Vittles readers who continue to enjoy the benefits of their service offerings. We will keep everyone posted on further developments.


    1. Does it have a way to work with analog phones? I’m trying to find a good, cheap, replacement for my TDM fxs card.

      [WM: What you need is an Analog Telephone Adapter. Google is your friend. Or visit voip-info.org forum for suggestions.]

    2. Skyetel has been moving to new banks of IP subnets for redundancy, etc. that are different than the default SIP trunks in IPBX2027. They also suggest using PJSIP two create just two trunks this way – in & out.

      Here are the added IPBX2027 steps I found to get the old disabled & the new two PJSIP trunks laid down/operational:

      1) Disable old SIP Skeytel trunks

      2) Add the following to the "/usr/local/sbin/iptables-custom" …

      /usr/sbin/iptables -A INPUT -s -j ACCEPT
      /usr/sbin/iptables -A INPUT -s -j ACCEPT
      /usr/sbin/iptables -A INPUT -s -j ACCEPT
      /usr/sbin/iptables -A INPUT -s -j ACCEPT
      /usr/sbin/iptables -A INPUT -s -j ACCEPT
      /usr/sbin/iptables -A INPUT -s -j ACCEPT
      /usr/sbin/iptables -A INPUT -s -j ACCEPT

      3) "iptables-restart"

      4) If you have a hardware firewall with say whitelisting, be sure to add these subnets & IP’s there as well of course.

      5) Follow Skyetel’s FreePBX PJSIP trunk directions:

      INBOUND: https://support.skyetel.com/hc/en-us/articles/4410765264791-FreePBX-13-Create-Inbound-Trunk

      OUTBOUND North America: https://support.skyetel.com/hc/en-us/articles/4410672050967-FreePBX-13-Create-Outbound-Trunk-for-North-America

      6) Create or change your Skyetel "IP Authentication -> IP Group" entry to use 5061 rather than 5060 to connect

      That’s it, and only two trunks using latest Skyetel infrastructure.

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