ChanSpy is a live call monitoring feature. In a typical FreePBX 17 setup, dialling 555 from an authorised handset or softphone allows the user to listen to another extension’s current call.

From an end-user perspective, it works like placing an internal call to a feature code.

What 555 does

• 555 is commonly used for listen-only call monitoring.
• It is normally used by supervisors or authorised staff.
• It only works when the target extension is already on an active call.
• It does not play back old calls or recordings.
• On some systems, the other party may hear a warning beep or announcement, depending on how the PBX has been configured.

Important points before using it

• Start from an idle handset or softphone.
• Do not try to use it while already on a call, otherwise the digits may be sent as DTMF to the current call instead of activating ChanSpy.
• You must have permission to use the feature.
• The target extension must already be speaking on a live call.
• The feature code in this guide is 555 because that is the code configured for this system. Some FreePBX systems use a different code if customised.

How to listen to a specific extension

The most common method is to dial the feature code followed by the extension number.

1. Lift the handset, press speaker, or open the softphone dial pad.
2. Dial 555 followed by the extension you want to monitor.

Example:

• To listen to extension 201, dial 555201
• To listen to extension 324, dial 555324

1. Wait for the call to connect.
2. If the extension is on a live call, audio from that call will be heard.
3. To stop listening, simply hang up or end the call in the softphone.

Alternative method on some phones

Some systems accept the digits in two stages:

1. Dial 555
2. Wait briefly
3. Enter the extension number, such as 201

If dialling 555201 in one go does not work on a particular handset, this two-step method is the next most common behaviour.

What happens when it works

• The monitoring call connects quietly.
• The user hears the call that the target extension is currently handling.
• In standard ChanSpy use, the monitoring user is not heard by the people on the call.
• When the monitored call ends, the ChanSpy session will usually end as well.

What the monitored user and caller experience

This depends on system configuration, but the common outcomes are:

• They do not hear the supervisor at all.
• They may hear a periodic beep to indicate monitoring is active.
• They are not normally transferred into a conference with the supervisor when using standard 555 listen-only monitoring.

Using ChanSpy from a desk phone

Typical process:

1. Make sure the phone is not already in use.
2. Press the speaker key or lift the receiver.
3. Dial the full code, for example 555201.
4. Listen to the call.
5. Press the end call key or replace the handset to stop.

Using ChanSpy from a softphone

The process is the same:

1. Open the dial pad.
2. Enter the feature code plus extension, for example 555201.
3. Start the call.
4. Listen to the audio.
5. End the call to stop monitoring.

Practical softphone tips:

• Keep the microphone muted as a precaution.
• Make sure the softphone is placing a new call to 555201, not sending those digits into another active call.
• Use headphones if discreet monitoring is required.

Examples

Common examples:

• Listen to extension 201: 555201
• Listen to extension 202: 555202
• Listen to extension 315: 555315

If the target extension is not on a call

If the extension is idle, the result may vary slightly depending on configuration:

• no audio is heard
• the call may end immediately
• a tone or message may be played
• the spy attempt may fail and return to idle

The most common reason ChanSpy appears not to work is simply that the target extension is not currently on an active call.

If only 555 is dialled

On some Asterisk or FreePBX configurations, dialling only 555 may try to spy on available active channels without specifying a particular extension. However, this behaviour is not always enabled or may not be useful for end users.

For normal day-to-day use, the most reliable method is:

• dial 555 plus the extension number

Stopping monitoring

To stop listening:

• hang up the handset
• press the phone’s end call key
• press the softphone end call button

There is no need to dial another code to exit.

Common limitations

• ChanSpy only works on live calls.
• It does not retrieve past conversations.
• It usually will not connect to an extension that is only ringing and has not yet answered.
• If the monitored call is transferred, parked, or changed into another type of call, the monitoring session may stop or the audio may change.
• Standard 555 use is normally listen-only. Whisper or barge functions, if available, are usually separate features or separately configured options.

Troubleshooting

Nothing happens when dialling 555

• The phone may not be authorised to use ChanSpy.
• The feature code may have been changed from 555.
• The phone may still be in another active call, so the digits are being treated as DTMF rather than a new call.

The call connects but there is silence

• The target extension is probably not on an active call.
• The target call may have just ended.
• The extension number dialled may be incorrect.

The call ends straight away

• The extension is not currently on a call.
• Permission to use ChanSpy may be restricted.
• The PBX may reject spying on that target.

A beep is heard during monitoring

• This is usually normal and indicates that monitoring alert tones are enabled.

The wrong extension was entered

• End the call.
• Redial with the correct full sequence, for example 555204.

Best practice for users

• Use ChanSpy only if authorised by company policy.
• Confirm the target extension is already on a live call before dialling.
• Dial the full code carefully, for example 555201.
• End the monitoring call as soon as it is no longer needed.
• Treat call monitoring as a controlled supervisory function, especially where privacy, training, or compliance rules apply.

In most everyday cases, the process is simply:

1. Start from an idle handset or softphone
2. Dial 555 plus the extension number
3. Listen to the live call
4. Hang up to stop