Paging Groups & Intercom Module Documentation

Module Overview (Technical)
Module Overview (Commercial/Business)
Module Overview (End User/Administrator)
Configuration Fields Reference
Call Flow / Logic Explanation
Common Scenarios & Examples
Model Context Protocol (MCP) AI Integration
Limitations & Important Notes
Troubleshooting Tips
Glossary

1. Module Overview (Technical)

What Are Paging Groups?

Paging Groups provide one-way or two-way audio broadcasting to multiple endpoints simultaneously. This includes:

Paging: One-way announcements to groups of phones
Intercom: Two-way communication (duplex mode)
Multicast: Network-level audio broadcasting to compatible devices

The Four Modes

Mode	Description	Use Case
Default	Standard SIP paging to selected extensions	Office announcements
Duplex	Two-way intercom communication	Warehouse communication
Multicast	RTP multicast to IP speakers	Factory floor PA
Hybrid	Both SIP extensions and multicast	Mixed environments

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                    Paging System Architecture                   │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  User dials: *80 (Paging Group Code)                            │
│       │                                                         │
│       ▼                                                         │
│  ┌──────────────────────────────────────────────────────────┐   │
│  │              Paging Group Lookup                         │   │
│  │  SELECT * FROM paging_groups WHERE code = '*80'          │   │
│  │  → Returns mode, members, settings                       │   │
│  └──────────────────────────────────────────────────────────┘   │
│       │                                                         │
│       ▼                                                         │
│  ┌──────────────────────────────────────────────────────────┐   │
│  │              Based on Mode                               │   │
│  │                                                          │   │
│  │  DEFAULT ──────────────────────────────────────────────  │   │
│  │    │                                                     │   │
│  │    ├─ Create conference room                             │   │
│  │    ├─ Set auto-answer headers                            │   │
│  │    ├─ Call each member extension                         │   │
│  │    └─ Bridge caller to conference                        │   │
│  │                                                          │   │
│  │  DUPLEX (Intercom) ────────────────────────────────────  │   │
│  │    │                                                     │   │
│  │    ├─ Same as default                                    │   │
│  │    └─ Enable two-way audio for all participants          │   │
│  │                                                          │   │
│  │  MULTICAST ────────────────────────────────────────────  │   │
│  │    │                                                     │   │
│  │    ├─ Answer caller                                      │   │
│  │    └─ Stream audio to multicast address (239.x.x.x)      │   │
│  │                                                          │   │
│  │  HYBRID ───────────────────────────────────────────────  │   │
│  │    │                                                     │   │
│  │    ├─ Call SIP extensions (like default)                 │   │
│  │    └─ Simultaneously stream to multicast                 │   │
│  │                                                          │   │
│  └──────────────────────────────────────────────────────────┘   │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

2. Module Overview (Commercial/Business)

Business Value

Paging Groups enable instant mass communication:

External Systems	Built-In Paging
Separate PA system	Integrated with PBX
Additional hardware	Uses existing phones
Manual intercom setup	Configured via UI
Limited scalability	Unlimited groups

Use Cases

Office Announcements
- “John Smith, please come to reception”
- Emergency notifications
- Company-wide messages
Warehouse/Manufacturing
- Foreman announcements
- Safety alerts
- Shift change notifications
Intercom Communication
- Reception to back office
- Security to all stations
- Medical triage coordination
School/Campus
- Classroom announcements
- Emergency lockdown
- Bell system integration

Feature Highlights

Feature	Benefit
Auto-Answer	Phones answer automatically—no user action needed
Mute Participants	One-way paging (listeners can’t interrupt)
PIN Protection	Restrict who can initiate pages
Recording	Record all announcements for compliance
Multicast	Broadcast to IP speakers without SIP overhead
Skip Busy	Don’t interrupt ongoing calls

3. Module Overview (End User/Administrator)

What Can You Do?

Create paging groups with assigned extension codes
Add/remove member extensions
Configure one-way (paging) or two-way (intercom) mode
Set up multicast for IP speakers
Protect pages with PIN codes
Enable recording of announcements

Navigate to PBX → Applications → Paging & Intercom in the main sidebar.
The list view displays all configured paging groups, detailing their dial Code, Name, Members count, Mode/Group Strategy, and active Status (Enabled/Disabled).
Click the + Add button in the upper toolbar to configure a new paging group.
Click any row or the edit icon to configure group extensions, broadcast strategies, auto-answer headers, or timeouts.

Paging & Intercom List View

User Workflow

┌─────────────────────────────────────────────────────────────────┐
│                 Creating a Paging Group                         │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  Step 1: Basic Settings                                         │
│  ├─ Code: 7001 (or *80)                                         │
│  ├─ Group Name: "Warehouse Overhead Paging"                    │
│  ├─ Strategy: Default (SIP auto-answer)                         │
│  └─ Timeout: 15 seconds                                         │
│                                                                 │
│  Step 2: Add Members                                            │
│  ├─ Search: "Warehouse" or "Floor"                              │
│  ├─ Select extensions from the searchable list                  │
│  └─ Counter shows "X of Y selected"                             │
│                                                                 │
│  Step 3: Caller ID Display                                      │
│  ├─ Name Template: Paging ${extension_name}                     │
│  └─ Number Template: ${extension_number}                        │
│                                                                 │
│  Step 4: Enable & Save                                          │
│  └─ Users dial 7001 → Member phones beep and auto-answer       │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Quick Tips

[!TIP] Auto-Answer Required: For paging to work, recipient IP phones must support and permit auto-answer SIP headers (Alert-Info: info=alert-autoanswer or Call-Info: answer-after=0).

[!TIP] Skip Busy: When configuring large teams, skip busy extensions so active customer calls are not interrupted by overhead broadcasts.

[!CAUTION] Multicast Network Config: Multicast paging requires proper LAN switch configuration (IGMP snooping and multicast routing) if speakers reside on different VLANs.

4. Configuration Fields Reference

Paging & Intercom Configuration Form

Basic Settings Tab

Field	Technical Description	User-Friendly Tooltip	Example	Required	Notes
Code *	Dialable extension or feature code for this paging group	Digits dialed by authorized users to initiate an announcement broadcast	`7001`, `*80`	Yes	Must be unique within the domain dialplan registry.
Group Name *	Human-readable identifier for the paging group	Clear label describing the department or area targeted	`Warehouse Overhead Paging`, `Executive Intercom`	Yes	Displayed in directories and audit logs.
Group Strategy (Mode)	Broadcast methodology and audio transmission mode	Operational audio mode (`Default` [One-way SIP], `Duplex` [Two-way intercom], or `Multicast` [RTP multicast])	`Default`	Yes	FreeSWITCH conference-driven auto-answer.
Multicast Address	IP multicast address and UDP port for streaming audio directly to network hardware speakers	Multicast address and port (active when Mode is Multicast)	`239.255.10.10:5000`	Conditional	Required only when Mode is set to Multicast.
Timeout (seconds) *	Maximum duration before automatically terminating page	Time limit in seconds for the broadcast session (5 - 120s)	`15`, `30`	Yes	FreeSWITCH `leg_timeout`. Protects against un-hung channels.
Caller ID Name	Display name presented to called endpoints	Caller ID name presented on receiving phone screens	`Overhead Page`	No	Overrides originator display name.
Caller ID Number	Display number presented to called endpoints	Caller ID number presented on receiving phone screens	`7001`	No	Overrides originator extension number.
Enabled	Master activation toggle	Instantly enable or disable this paging group	`Yes` / `No` (toggle)	Yes	Default: Yes.
Members (Extensions)	Multi-select list of extensions included in this broadcast group	Select which phone extensions will auto-answer when this group is called	Multi-selection list	Yes	Recipients receive native `sip_auto_answer=true`.

Advanced Settings Tab

Audio & Media Settings

Field	Technical Description	User-Friendly Tooltip	Default	Example	Notes
Audio Codec	RTP audio codec used for the broadcast session	Preferred audio codec for the stream	`PCMU`	`PCMU`, `PCMA`, `G722`, `OPUS`	Multicast speakers must support the selected codec.
Speaker Volume	Audio output volume adjustment applied to broadcast legs	Speaker volume adjustment (-5 to +5)	`5`	`0` (normal), `5` (loud)	Sets FreeSWITCH `speak_volume` leg channel variable.
Pre-Page Announcement	Audio recording played to caller/listeners before bridging	Audio prompt played prior to the live broadcast	None	`beep.wav`, `chime.wav`	Uploaded via Sound Prompts / Voice Recordings.
Record Session	Records the complete paging session to storage	Enable or disable automatic recording of announcements	`Off`	Toggle (`On`/`Off`)	Saves audio via FreeSWITCH `record_session=true`.
Skip Busy Extensions	Prevents interrupting active calls on recipient endpoints	Do not ring or auto-answer extensions currently on an active call	`Off`	Toggle (`On`/`Off`)	FreeSWITCH `skip_busy=true` originate channel variable.

5. Call Flow / Logic Explanation

Standard Paging Flow (Default Mode)

┌─────────────────────────────────────────────────────────────────┐
│                  Standard Paging Flow                           │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  1. User dials *80 (paging group code)                          │
│     │                                                           │
│     ▼                                                           │
│  2. Check PIN requirement (if configured)                       │
│     ├─ PIN required → Prompt for PIN                           │
│     │   ├─ Correct → Continue                                  │
│     │   └─ Wrong → "Invalid PIN" + hangup                      │
│     └─ No PIN → Continue                                       │
│     │                                                           │
│     ▼                                                           │
│  3. Play pre-announcement (if configured)                       │
│     │                                                           │
│     ▼                                                           │
│  4. Create dynamic conference for this page                     │
│     │                                                           │
│     ▼                                                           │
│  5. For each member extension:                                  │
│     ├─ Check if busy (if skip_busy enabled)                     │
│     ├─ Set auto-answer SIP headers                              │
│     └─ Bridge to conference (muted if mute_participants)        │
│     │                                                           │
│     ▼                                                           │
│  6. Wait for specified timeout for endpoints to answer          │
│     │                                                           │
│     ▼                                                           │
│  7. Caller speaks → Audio broadcast to all answered phones      │
│     │                                                           │
│     ▼                                                           │
│  8. Caller hangs up → Conference ends, all legs disconnect      │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Multicast Flow

┌─────────────────────────────────────────────────────────────────┐
│                    Multicast Paging Flow                        │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  1. User dials *85 (multicast paging group)                     │
│     │                                                           │
│     ▼                                                           │
│  2. Answer caller                                               │
│     │                                                           │
│     ▼                                                           │
│  3. Start RTP stream to multicast address:                      │
│     Address: 239.255.10.10:5000                                 │
│     Codec: PCMU (G.711µ)                                        │
│     │                                                           │
│     ▼                                                           │
│  4. IP speakers (subscribed to 239.255.10.10) receive audio     │
│     │                                                           │
│     ▼                                                           │
│  5. Caller hangs up → Stream stops                              │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

6. Common Scenarios & Examples

Scenario 1: Office-Wide Announcement

Setup:

Setting	Value
Code	*80
Name	All Office
Mode	Default
Members	1001-1050 (all office extensions)
Auto Answer	✓
Mute Participants	✓
Skip Busy	✓

Result: Dial *80, all available phones auto-answer (muted), announcement plays.

Scenario 2: Warehouse Intercom

Setup:

Setting	Value
Code	*70
Name	Warehouse Intercom
Mode	Duplex
Members	2001, 2002, 2003 (warehouse phones)
Intercom Mode	✓
Mute Participants	✗ (allow responses)

Result: Dial *70, all warehouse phones connect for two-way conversation.

Scenario 3: Factory Floor PA System

Setup:

Setting	Value
Code	*85
Name	Factory PA
Mode	Multicast
Multicast Address	239.255.10.10
Port	5000
Codec	PCMU

Result: Dial *85, audio streams to all IP speakers configured for that multicast group.

Scenario 4: Protected Emergency Announcement

Setup:

Setting	Value
Code	*911
Name	Emergency Broadcast
Mode	Hybrid
PIN Code	9911
Members	ALL extensions
Multicast	(also to PA speakers)
Recording	✓

Result: Only authorized users with PIN can trigger emergency broadcast to all phones and speakers. All broadcasts recorded.

7. Model Context Protocol (MCP) AI Integration

Paging and Intercom groups are exposed via the Model Context Protocol (MCP) for programmatic administration, membership audits, and direct voice broadcast origination by authorized AI operators.

Available MCP Tools

Tool Name	Operation	Description	Access Level
`list_paging_groups`	Query	List all paging and intercom groups, audio modes, member counts, and multicast addresses.	Read-Only
`get_paging_group_status`	Query	Retrieve full group details including individual member extensions and audio parameters.	Read-Only
`create_paging_group`	Provisioning	Create a new paging or two-way intercom group with auto-answer headers and custom timeouts.	Admin / Superadmin
`update_paging_group`	Management	Add/remove member extensions, change broadcast audio mode, or adjust timeout limits.	Admin / Superadmin
`delete_paging_group`	Deprovisioning	Remove a paging group from the PBX.	Superadmin
`page_broadcast`	Live Telephony	Trigger a real-time live page broadcast originating from a specific extension to a paging group code.	Operator / Admin

Tool Definitions & Parameter Reference

`create_paging_group`

Provisions an auto-answer broadcast group within the domain.

{
  "name": "create_paging_group",
  "description": "Create a new Paging / Intercom group to broadcast voice messages or execute two-way intercom to multiple extensions with auto-answer.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "code": { "type": "string", "description": "Dial code for the paging group (e.g. '*84', '800', '99')." },
      "name": { "type": "string", "description": "Name of the paging group (e.g. 'Warehouse Speakers')." },
      "members": {
        "type": "array",
        "items": { "type": "string" },
        "description": "Array of member extension numbers (e.g. ['2001', '2002', '2003'])."
      },
      "mode": {
        "type": "string",
        "enum": ["default", "intercom", "multicast", "duplex"],
        "description": "Paging mode: 'default' (one-way), 'intercom' (two-way), 'multicast' (RTP stream), 'duplex' (conference)."
      },
      "timeout": { "type": "number", "description": "Maximum broadcast duration in seconds (default: 30)." },
      "autoAnswer": { "type": "boolean", "description": "Send SIP auto-answer headers (Call-Info / Alert-Info)." }
    },
    "required": ["code", "name", "members"]
  }
}

Safety Safeguards & Number Uniqueness

Domain Number Collision Prevention: The service enforces validateNumberUniqueness(code, domain.id, 'paging_groups') against public.dialplan_registry. Paging codes cannot collide with Extensions, Conferences, Parking Lots, Speed Dials, or Feature Codes in the same domain.
Auto Dialplan Synchronization: Changes immediately sync to public.dialplan_registry and reload Telephony Server XML configuration so endpoints can dial the paging code without server restart.

Example AI Assistant Prompts & Workflow

Example 1: Creating a Warehouse Intercom Group

Admin Prompt:
*“Create a two-way intercom group with code 85 named ‘Warehouse Floor’ for extensions 3010, 3011, and 3012 with a 60-second timeout.”

AI Tool Execution:

{
  "tool": "create_paging_group",
  "arguments": {
    "code": "*85",
    "name": "Warehouse Floor",
    "members": ["3010", "3011", "3012"],
    "mode": "intercom",
    "timeout": 60,
    "autoAnswer": true
  }
}

MCP Response:

{
  "success": true,
  "data": {
    "code": "*85",
    "name": "Warehouse Floor",
    "mode": "intercom",
    "memberCount": 3,
    "message": "Paging group *85 created successfully."
  }
}

8. Limitations & Important Notes

Technical Limitations

[!WARNING] Auto-Answer Support: Not all SIP phones support auto-answer. Older or basic phones may not activate.

[!WARNING] Multicast Network Requirements: Multicast requires IGMP-enabled switches and proper network configuration.

[!IMPORTANT] Codec Compatibility: Multicast endpoints must support the configured codec. PCMU (G.711µ) has widest support.

Best Practices

Test Auto-Answer: Verify phones actually auto-answer before relying on paging
Network Planning for Multicast: Work with network team to enable IGMP snooping
PIN Protection: Use PINs for high-impact pages (emergency, company-wide)
Skip Busy: Always enable to avoid interrupting important calls
Keep Groups Focused: Create smaller, targeted groups rather than one huge group

Phone Configuration

For auto-answer to work, phones typically need:

Auto-answer header support enabled
Intercom mode enabled in phone settings
Correct SIP headers: Alert-Info: info=auto-answer or similar

9. Troubleshooting Tips

Common Issues

Symptom	Possible Cause	Solution
Phone doesn’t answer	Auto-answer not supported	Check phone model/settings
No audio on page	Codec mismatch	Verify codec compatibility
Multicast not working	Network issue	Check IGMP, switch config
Only some phones answer	Skip busy + busy phones	Expected behavior
“Invalid PIN”	Wrong PIN entered	Verify correct PIN
Recording not created	Path permissions	Check directory permissions

Diagnostic SQL

List paging groups:

SELECT pg.code, pg.name, pg.mode, pg.enabled,
       COUNT(m.id) as member_count
FROM public.paging_groups pg
LEFT JOIN public.paging_group_members m ON pg.id = m.paging_group_id
WHERE pg.domain_id = [domain_id]
GROUP BY pg.id
ORDER BY pg.code;

Check members of a group:

SELECT pgm.extension, e.description
FROM public.paging_group_members pgm
JOIN public.sip_extensions e ON pgm.extension = e.extension
WHERE pgm.paging_group_id = [group_id];

Telephony Server Diagnostics

Check active conferences (paging uses conferences):

fs_cli -x "conference xml_list"

Debug multicast:

# Check if multicast traffic is being sent
tcpdump -i eth0 host 239.255.10.10 and udp port 5000

10. Glossary

Term	Definition
Paging	One-way audio broadcast to multiple phones
Intercom	Two-way audio communication between phones
Multicast	Network-level broadcast using IP multicast (239.x.x.x addresses)
Auto-Answer	Phone feature that answers incoming calls automatically
Duplex	Two-way audio communication mode
IGMP	Internet Group Management Protocol—enables multicast on switches
TTL	Time To Live—how many network hops multicast packets can travel
PCMU	G.711µ audio codec—widely supported, good quality
RTP	Real-time Transport Protocol—carries audio over IP networks
PA System	Public Address system—speakers for announcements
Barge-In	Ability to interrupt an ongoing announcement
Skip Busy	Don’t page extensions that are on active calls

Documentation last updated: January 2026

Paging Groups & Intercom Module Documentation

Table of Contents

1. Module Overview (Technical)

What Are Paging Groups?

The Four Modes

Architecture

2. Module Overview (Commercial/Business)

Business Value

Use Cases

Feature Highlights

3. Module Overview (End User/Administrator)

What Can You Do?

Navigation

User Workflow

Quick Tips

4. Configuration Fields Reference

Basic Settings Tab

Advanced Settings Tab

Audio & Media Settings

5. Call Flow / Logic Explanation

Standard Paging Flow (Default Mode)

Multicast Flow

6. Common Scenarios & Examples

Scenario 1: Office-Wide Announcement

Scenario 2: Warehouse Intercom

Scenario 3: Factory Floor PA System

Scenario 4: Protected Emergency Announcement

7. Model Context Protocol (MCP) AI Integration

Available MCP Tools

Tool Definitions & Parameter Reference

create_paging_group

Safety Safeguards & Number Uniqueness

Example AI Assistant Prompts & Workflow

Example 1: Creating a Warehouse Intercom Group

8. Limitations & Important Notes

Technical Limitations

Best Practices

Phone Configuration

9. Troubleshooting Tips

Common Issues

Diagnostic SQL

Telephony Server Diagnostics

10. Glossary

`create_paging_group`