How to install dahdi in vicidial — Complete Step-by-Step Guide

How to install dahdi in vicidial — Complete Step-by-Step Guide

Introduction

This guide explains how to install dahdi in vicidial on Linux servers. It is written for VoIP engineers, system/telephony administrators, call center integrators, and DevOps professionals. You’ll get a practical, step-by-step walkthrough: prerequisites, download commands, compilation, configuration, testing, and troubleshooting.

Table of Contents

Quick overview (what DAHDI and ViciDial do)

  • DAHDI (Digium/Asterisk Hardware Device Interface) provides kernel drivers and tools for telephony cards and T1/E1/analog interfaces.

  • VICIdial is an open-source call-center suite that uses Asterisk as the telephony engine.
     Together, DAHDI + Asterisk + VICIdial enable PSTN connectivity (PRI, BRI, FXO/FXS) for on-premise dialer setups.

Before you begin — supported OS and kernel notes

  • Recommended: CentOS / Rocky / AlmaLinux 7 or 8 (many community tutorials target CentOS 7).

  • Ensure the running kernel has matching kernel-headers / kernel-devel installed before compiling DAHDI or Asterisk. Without matching kernel headers you will get build errors. (LFCS Certification eBook)

Required packages & system prep

Install development tools and dependencies:

If you have multiple spans, create groups and use channel => ranges accordingly. After editing, reload Asterisk CLI:

				
					yum groupinstall -y "Development Tools"
yum install -y wget vim net-tools epel-release
yum install -y gcc gcc-c++ make perl perl-devel libxml2-devel sqlite-devel
yum install -y kernel-devel kernel-headers numactl-devel ncurses-devel

Reboot if you just installed a new kernel so uname -r and kernel-devel match. Many DAHDI build failures stem from header/kernel mismatches. (Asterisk Community)

Step 1 — Download DAHDI (official tarball)

Download the DAHDI source (use the latest stable from Asterisk project or vendor tarballs). Example:

				
					cd /usr/src
wget https://downloads.asterisk.org/pub/telephony/dahdi-linux-complete/dahdi-linux-complete-2.11.0+2.11.0.tar.gz
tar -xzf dahdi-linux-complete-2.11.0+2.11.0.tar.gz
cd dahdi-linux-complete-2.11.0+2.11.0

Official DAHDI tarballs and the dahdi-linux-complete bundle are hosted on downloads.asterisk.org. Use that as the authoritative source for releases. (Asterisk Downloads)

Step 2 — Build & install DAHDI

From the extracted directory run:

				
					make all
make install
make config

After make install load the module:

				
					modprobe dahdi
modprobe dahdi_dummy   # optional for testing if no hardware present
service dahdi start    # or systemctl enable --now dahdi

These are the canonical DAHDI build steps used in Asterisk documentation and installation guides. (Asterisk Documentation)

Step 3 — Install DAHDI tools and check hardware

Install the DAHDI tools (if not in the combined tarball):

For more control or custom setups, go manual. This method lets you select specific versions and troubleshoot deeply.

Begin by gathering system info. Know your OS bit size—critical for compatible files.

				
					cd /usr/src/dahdi-linux-complete-*/tools
make all && make install
dahdi_cfg -vv
dahdi_genconf -v

dahdi_cfg -vv lists configured spans and hardware. dahdi_genconf can auto-generate /etc/dahdi/system.conf for many common cards. Use them to confirm kernel modules and board firmware loaded correctly. (STRIKER24X7- Vicidial Asterisk Blog)

Step 4 — Install LibPRI and Asterisk (brief)

LibPRI provides PRI signaling support. Example:

				
					cd /usr/src
wget https://downloads.asterisk.org/pub/telephony/libpri/libpri-1.6.0.tar.gz
tar xzf libpri-1.6.0.tar.gz && cd libpri-1.6.0
make && make install

Install Asterisk (choose a supported Asterisk version for your VICIdial release). Compile Asterisk with DAHDI support (include menuselect options like chan_dahdi). Many VICIdial scratch install guides document Asterisk version pairings and required contrib scripts. (Ucartz)

Step 5 — Configure chan_dahdi.conf (Asterisk side)

Edit /etc/asterisk/chan_dahdi.conf to match your spans and channels. Basic fields:

  • signalling (e.g., pri_cpe, pri_net)

  • group and channel mappings

  • context where calls enter Asterisk (e.g., from-pstn)

Example snippet:

				
					[channels]
usecallerid=yes
switchtype=euroisdn
signalling=pri_cpe
group=1
context=from-pstn

If Asterisk loses DAHDI connectivity after loading chan_dahdi.conf, verify dahdi_cfg output and Asterisk logs — a common cause is mismatched channel definitions or attempting to use channels that are already in use. (Asterisk Community)

Step 6 — Generate DAHDI config (system.conf) & verify

Run:

				
					dahdi_genconf -v
dahdi_cfg -vv
cat /etc/dahdi/system.conf

Ensure span lines and span protocols match your card (E1/T1/analog). If dahdi_cfg shows “No hardware” recheck kernel modules and modprobe dahdi. Common troubleshooting commands:

				
					lsmod | grep dahdi
dmesg | grep -i dahdi
journalctl -xe

Use dahdi_tool and dahdi_monitor for diagnostics. (STRIKER24X7- Vicidial Asterisk Blog)

Step 7 — Integrate with VICIdial

  1. In VICIdial Admin → Carriers add an entry that points to your Asterisk trunk (SIP or DAHDI mapping).
  2. For DAHDI direct inbound mapping, set the carrier to use the Asterisk context you defined in chan_dahdi.conf.
  3. Use VICIdial’s “Manage Campaigns” and “Phones” to map extensions and dialplan behavior.
     VICIdial often expects Asterisk to expose channels via standard contexts—confirm dialplan matches VICIdial’s incoming call flow. Many community guides show full “scratch install” flows combining Asterisk, DAHDI, and VICIdial. (STRIKER24X7- Vicidial Asterisk Blog)

Testing calls (basic)

  • Make a loopback/test call from PSTN to a configured DID and trace in asterisk -rvvv.
  • Use dahdi_test if your hardware vendor supports it.
  • Check /var/log/asterisk/full for channel up/down and call progress.
  • Verify audio with core show channels verbose inside Asterisk CLI.

Common errors & fixes

Common errors & fixes
  1. Build fails: missing kernel headers — install kernel-devel and reboot. Ensure uname -r matches the installed kernel-devel. (LFCS Certification eBook)
  2. modprobe dahdi works but DAHDI not loaded on boot — enable service via systemctl enable dahdi or add modprobe entries. Check /etc/modules-load.d/. (Vicidial)
  3. No audio / one-way audio — verify codecs, NAT settings, firewall rules, and DAHDI span status. Use dahdi_monitor to inspect framing/signal. (CyburDial – Dialer.one)
  4. Asterisk shows ‘Unable to create channel of type DAHDI’ — ensure chan_dahdi.so is compiled and loaded, and dahdi_cfg lists available channels. Rebuild Asterisk with DAHDI support if missing. (STRIKER24X7- Vicidial Asterisk Blog)

Reinstalling or updating DAHDI (safe steps)

  • Backup /etc/dahdi and /etc/asterisk/chan_dahdi.conf.
  • Remove old modules: make uninstall in the DAHDI source (if available) or rmmod dahdi.
  • Install new tarball following the same build steps.
  • Re-run dahdi_genconf and restart Asterisk.

Best practices & hardening

  • Use a test server to compile and validate before touching production.
  • Keep kernel, dahdi-tools, and asterisk versions compatible.
  • Automate builds with scripts and capture make logs for audits.
  • Restrict SSH and management ports; keep PBX systems behind VPNs when possible.
  • Document card firmware versions and driver patches if you apply vendor-specific patches.

Example checklist (quick)

  • Backup configs
  • Install kernel-devel (matching kernel)
  • Download & extract dahdi-linux-complete
  • make all && make install && make config
  • modprobe dahdi
  • dahdi_genconf && dahdi_cfg -vv
  • Configure chan_dahdi.conf
  • Restart Asterisk, verify channels

FAQ (short)

Q: Can I install DAHDI without root?
 A: No — you need root to compile modules, write /lib/modules, and load kernel modules.

Q: Do I need DAHDI for SIP trunks?
 A: No — DAHDI is for hardware PSTN interfaces. SIP trunks do not require DAHDI.

Q: What if my Digium/Sangoma card isn’t recognized?
 A: Check vendor drivers/firmware and vendor-specific instructions. Use vendor support guides and Sangoma’s compilation notes. (help.sangoma.com)

Troubleshooting checklist (commands)

				
					uname -r
rpm -qa | grep kernel
yum install "kernel-devel-$(uname -r)"
lsmod | grep dahdi
dahdi_cfg -vv
dmesg | tail -n 50
asterisk -rvvv

Detailed CentOS 7/8 installation example (scratch install)

This section shows a compact, practical flow for a CentOS/RHEL family server (common for many VICIdial installations). It assumes a fresh minimal install with network access and sudo/root privileges.

  1. Update system and install deps:
				
					yum -y update
yum -y groupinstall "Development Tools"
yum -y install epel-release
yum -y install wget vim git vim net-tools
yum -y install gcc gcc-c++ make kernel-devel kernel-headers
yum -y install libuuid-devel libxml2-devel sqlite-devel
  1. Reboot if kernel packages were changed. Verify:
				
					uname -r
rpm -qa | grep kernel
yum install "kernel-devel-$(uname -r)" || yum install kernel-devel
  1. Get DAHDI bundle and extract:
				
					cd /usr/src
wget https://downloads.asterisk.org/pub/telephony/dahdi-linux-complete/dahdi-linux-complete-current.tar.gz -O dahdi.tar.gz
tar -xzf dahdi.tar.gz
cd dahdi-linux-complete-*
  1. Compile and install:
				
					make all && make install && make config
modprobe dahdi
modprobe dahdi_dummy
systemctl enable --now dahdi
  1. Install LibPRI and Asterisk (short):
				
					cd /usr/src
wget https://downloads.asterisk.org/pub/telephony/libpri/libpri-current.tar.gz -O libpri.tar.gz && tar xzf libpri.tar.gz && cd libpri-*
make && make install
# Asterisk (pick your supported version)
wget https://downloads.asterisk.org/pub/telephony/asterisk/asterisk-18.*/asterisk-18.*.tar.gz
tar xzf asterisk-18.*.tar.gz && cd asterisk-*
contrib/scripts/install_prereq install
./configure
make menuselect
make && make install && make samples && make config
systemctl enable --now asterisk

Example chan_dahdi.conf mapping for a PRI span (E1/T1)

Below is a sample /etc/asterisk/chan_dahdi.conf snippet for a PRI with 30 channels (E1) using EuroISDN:

				
					[channels]
language=en
context=from-pstn
tonezone=us
usecallerid=yes
group=1
signalling=pri_cpe
channel => 1-15,17-31

If you have multiple spans, create groups and use channel => ranges accordingly. After editing, reload Asterisk CLI:

				
					asterisk -rx "module reload chan_dahdi.so"
asterisk -rvvv
dahdi_cfg -vv

vicidial meetme and conferencing notes

Older VICIdial setups used MeetMe which required DAHDI timing devices. Modern Asterisk supports ConfBridge (which may not require DAHDI timing), but if you use meetme with DAHDI timing ensure dahdi_cfg reports timers available. For campaigns using local conferencing, confirm the app modules (app_meetme or app_confbridge) are installed in Asterisk and accessible to VICIdial. Use module show like meetme or module show like confbridge in the Asterisk CLI to confirm.

Logs, sample troubleshooting outputs & how to interpret them

Common log: DAHDI module error at boot

				
					Feb 12 10:12:01 mypbx kernel: dahdi: module license 'GPL' taints kernel.
Feb 12 10:12:01 mypbx kernel: dahdi: loading out-of-tree module taints kernel.
  • Meaning: You compiled out-of-tree modules (normal). If device nodes are missing, check /dev/dahdi or /proc/dahdi.

     

  • Fixes: Ensure make install wrote modules into /lib/modules/$(uname -r)/kernel/drivers/telephony and run depmod -a then modprobe dahdi.

Asterisk error when loading chan_dahdi

				
					[Oct 01 10:45:12] ERROR[1234]: chan_dahdi.c:1234 load_module: Unable to load chan_dahdi.so: /usr/lib/asterisk/modules/chan_dahdi.so: undefined symbol: xxx
  • Meaning: Binary mismatch or missing DAHDI libraries. Rebuild Asterisk after DAHDI is installed. Use ldd chan_dahdi.so to see missing libraries.

No channels found in dahdi_cfg

				
					# dahdi_cfg -vv
No DAHDI hardware found.
  • Meaning: driver not loaded or firmware missing. Check dmesg for device recognition and run dahdi_genconf to auto-detect card definitions.

Vendor-specific notes

  • Sangoma/Digium cards: often vendor-provided RPMs exist for certain distros. Vendor drivers may include firmware and utilities. Check Sangoma support for Sangoma-specific DAHDI builds. (help.sangoma.com)

  • OpenVox / Others: OpenVox and other vendors sometimes ship patched DAHDI bundles — follow vendor docs for downloading their dahdi-linux-complete tarball. (OpenVox)

Recompiling kernel modules after kernel upgrade (recompile DAHDI kernel)

If you update the kernel you must rebuild DAHDI against the new kernel headers. Typical flow:

				
					yum update kernel
reboot
yum install "kernel-devel-$(uname -r)"
cd /usr/src/dahdi-linux-complete-*
make clean
make all && make install && depmod -a
modprobe dahdi
systemctl restart dahdi
systemctl restart asterisk

If modules fail to build due to API changes, check for a newer DAHDI release on downloads.asterisk.org. (Asterisk Downloads)

How to reinstall DAHDI safely (step-by-step)

  1. Stop services: systemctl stop asterisk dahdi

  2. Backup configs:

				
					tar -czf /root/dahdi-backup-$(date +%F).tgz /etc/dahdi /etc/asterisk/chan_dahdi.conf /var/spool/asterisk/monitor
  1. Uninstall older DAHDI (if supported):
				
					cd /usr/src/dahdi-linux-complete-*
make uninstall || true
rmmod dahdi || true
  1. Install new DAHDI using the standard make flow and then verify with dahdi_cfg.

Monitoring & maintenance tips

  • Use dahdi_tool for line status and alarm monitoring.

  • Schedule monthly checks of dmesg for DAHDI warnings.

  • Keep a version matrix document recording kernel, DAHDI, libpri, and Asterisk versions for each server.

Appendix A — Useful scripts

A small script to automate download, compile and install DAHDI (use with caution):

				
					#!/bin/bash
set -e
cd /usr/src
wget -O dahdi.tar.gz https://downloads.asterisk.org/pub/telephony/dahdi-linux-complete/dahdi-linux-complete-current.tar.gz
tar xzf dahdi.tar.gz
cd dahdi-linux-complete-*
make all && make install && make config
depmod -a
modprobe dahdi

Appendix B — Sample Vicidial Asterisk trunk mapping for DAHDI inbound

In many VICIdial installations you map incoming DID/PRIs to VICIdial contexts:

  • Asterisk from-pstn context should route to Goto(VICIDIAL-CONNECT,…) or call AGI scripts used by VICIdial for lead handling.

     

  • Configure carriers in VICIdial Admin to point to the Asterisk server and test call flow using the VICIdial “Inbound” testing tools.

Performance tuning and hardware tips

Performance tuning and hardware tips

 

  • For high-density dialers (hundreds of concurrent channels) use dedicated telephony-grade PCIe cards and multi-CPU servers. CPU, memory, and disk IO all matter when call recording is enabled.

     

  • Prefer SSD for Asterisk recording storage when budget allows; spinning disks may bottleneck on many concurrent recordings.

     

  • If using DAHDI PRI spans, check for CRC errors and alarms using dahdi_tool and vendor diagnostics. Framing errors often indicate physical wiring or carrier issues.

     

  • Monitor system load with top, htop, and iostat. Tune Linux network stack (e.g., increase file descriptors, tune ulimit, and tune sysctl for high connection counts).

Mapping DAHDI channels to Vicidial campaigns (practical)

  • Allocate a channel range per campaign or per trunk group in chan_dahdi.conf using group and channel => ranges.

     

  • In VICIdial, create a carrier entry for the trunk and map Inbound routing to the Asterisk context that receives DAHDI calls.

     

  • For outgoing (manual or predictive) campaigns using DAHDI, ensure local channel selection doesn’t overlap with inbound-only reserved channels.

     

  • Example: Reserve channels 1–50 for Campaign A by assigning them to group=10 and manipulating dialplan priorities to prefer these channels.

Extended FAQ (more)

Q: Will DAHDI installation affect my existing SIP trunks?
 A: Not if you carefully configure chan_dahdi.conf channels and Asterisk dialplan contexts. DAHDI is orthogonal to SIP modules; both can coexist in the same Asterisk instance.

Q: How do I detect hardware alarms on T1/E1?
 A: Use dahdi_monitor and dahdi_tool for real-time status. Look for CRC or LOS (loss of signal) messages in dmesg or the DAHDI tools output.

Q: Is it safe to run make all on production?
 A: Compiling on production is common but risky. Better to build on a staging server with identical kernel version and then deploy modules to production.

Advanced debugging: reading DAHDI & Asterisk traces

When troubleshooting complex issues, capture traces and read them systematically.

  1. Enable verbose and debug in Asterisk CLI:
				
					asterisk -rvvvv
core set verbose 5
core set debug 5
logger reload
tail -f /var/log/asterisk/full

Capture DAHDI kernel messages:

				
					dmesg --ctime | grep -i dahdi
journalctl -k -b | grep -i dahdi
  1. Use tcpdump for SIP / RTP debugging if you have mixed SIP and DAHDI channels:
				
					tcpdump -i eth0 -n host x.x.x.x and port 5060 -w sip.pcap

Open the pcap in Wireshark to inspect RTP streams and SIP signalling. This helps when you see one-way audio or RTP SSRC issues.

Example: Interpreting dahdi_cfg output

Channelmap:

				
					Group 1: 1-15,17-31  (span 1: OK)
Timing source: /dev/dahdi/1
  • If spans show LOF or AIS flags, these indicate line faults from the telco side. Coordinate with carrier to fix wiring or framing settings.

Security & compliance reminders

  • Don’t expose Asterisk management interfaces to the public internet. Use VPNs or IP ACLs for VICIdial admin panels and Asterisk AMI connections.

  • For call recordings, comply with local regulations for consent and data retention. Store recordings in encrypted volumes if required by policy.

  • Patch and update OS packages regularly and rotate credentials for admin accounts and database users.

If something cannot be completed

If you encounter vendor-locked drivers, compile errors that reference proprietary vendor code, or proprietary firmware that you cannot obtain, escalate to vendor support. For questions about legal compliance for call recordings or telecom regulations, consult legal counsel. This document does not replace vendor or legal guidance.

Glossary (quick)

  • DAHDI: Digium/Asterisk Hardware Device Interface — kernel drivers/tools for telephony cards.

  • chan_dahdi: Asterisk channel driver that interfaces with DAHDI devices.

  • span: A T1/E1 physical link containing multiple channels.

  • dahdi_genconf: Utility to auto-generate /etc/dahdi/system.conf from detected hardware.

  • dahdi_cfg: Utility to load DAHDI configuration and list channels.

Contact & further learning

  • Use community forums like the VICIdial forums and Asterisk community to search for version-specific notes. Many issues are reproducible and documented in forum threads.

  • Consider reading Asterisk project docs and Sangoma vendor notes for maintenance and advanced topics. (Asterisk Documentation)

Conclusion & final checklist

This guide has shown how to install dahdi in vicidial by preparing the OS, installing dependencies, compiling and installing DAHDI, configuring Asterisk’s chan_dahdi, integrating with VICIdial, and running tests. Follow the checklists above, keep backups, and validate on a staging system before going live.

Final production checklist (condensed):

  1. Kernel headers and kernel-devel installed and matched.

  2. DAHDI compiled & modprobe loaded.

  3. dahdi_genconf produced a correct /etc/dahdi/system.conf.

  4. Asterisk chan_dahdi loads and dahdi_cfg -vv shows channels.

  5. VICIdial carriers and inbound contexts mapped and tested.

Acknowledgements

Many community tutorials, the Asterisk project, and VICIdial forums provided practical help and worked examples used to inform this article.

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