System General Settings

The system general settings can be applied globally to Yeastar Cloud PBX

System Preference

Configure the preferences settings that will be applied globally to the system.

Go to Settings > PBX > General > Preferences to configure the system preferences.

General Preference

OptionDescription
Max Call DurationSelect the global maximum call duration.
Note:

The precedence of Max Call Duration(s) (Global v.s. Extension):

  • For internal calls: The Max Call Duration(s) setting of the caller's extension takes precedence.
  • For outbound calls: The Max Call Duration(s) setting of the caller's extension takes precedence.
  • For inbound calls: The global Max Call Duration(s) setting takes precedence.
Attended Transfer Caller IDThe Caller ID that will be displayed on the recipient's phone. For example, Phone A (transferee) calls Phone B (transfer), and Phone B transfers the call to Phone C (recipient). If set to Transfer, the Caller ID displayed will be Phone B's number; if set to Transferee, Phone A's number will be displayed.
Flash EventSet which event will be triggered by pressing the hook flash:
  • 3-way Calling
  • Call Transfer
Virtual Ring Back ToneOnce enabled, when the caller calls out with cellular trunks, the caller will hear the virtual ring back tone generated by the system before the callee answers the call.
Distinctive Caller IDWhen the incoming call is routed from Ring Group, Queue or IVR, the Caller ID would display where it comes from.
Match Route Permission When Seizing a LineIf checked, when users seize a line to place an outbound call, the call will succeed only when the route permission is matched.
FXO Mode

Select a mode to set the On Hook Speed, Ringer Impedance, Ringer Threshold, Current Limiting, TIP/RING voltage, adjustment, Minimum Operational Loop Current, and AC Impedance as predefined for your country's analog line characteristics.

The default setting is FCC for USA.
Tone RegionSelect your country or nearest neighboring country to enable the default dial tone, busy tone, and ring tone for your region.
DTMF DurationSet the duration of a DTMF tone on the FXO trunk.
DTMF GapSet the interval between each DTMF tone on the FXO trunk.

Extension Preference

Below are default extension ranges. You can change the extension range according to your needs.Note: PBX treats Ring Group, Paging Group, Conference, Queue as extensions. Extension users can dial the extension numbers to reach them directly.

Extension TypeDefault Range
User Extensions1000 - 5999
Account Trunk6100 - 6199
Ring Group Extensions6200 - 6299
Paging Group Extensions6300 - 6399
Conference Extensions6400 - 6499
IVR Extensions6500 - 6599
Queue Extensions6700 - 6799

Feature Code

Feature codes are used to enable and disable certain features available in the Yeastar Cloud PBX. Extension users can dial feature codes on their phones to use that particular feature.

Go to Settings > PBX > General > Feature Code to view or change the feature code settings.

  • Feature Code Digit Timeout: The timeout to input next digit. The default is 4000 ms.

Default Feature Codes

Recording
One Touch Recording*1
Auto Recording Switch*00
Call Forwarding
Reset to Defaults*70
Enable Forward All Calls*71
Disable Forward All Calls*071
Enable Forward When Busy*72
Disable Forward When Busy*072
Enable Forward No Answer*73
Disable Forward No Answer*073
Voicemail
Check Voicemail*2
Voicemail for Extension**
Voicemail Main Menu*02
Transfer
Blind Transfer*03
Attended Transfer*3
DND
Enable Do Not Disturb*74
Disable Do Not Disturb*074
Call Pickup
Call Pickup*4
Extension Pickup*04
Queue
Switch Dynamic Agent's Login Status*75
Switch Agent's Pause Status*075
Busy Camp-on
Enable Busy Camp-on*79
Disable Busy Camp-on*079
Time Condition
Time Condition Override*8
Intercom
Intercom*5
Call Monitor
Listen*90
Whisper*91
Barge-in*92
Call Parking
Call Parking*6
Directed Call Parking*06
Parking Extension Range6900-6999
Hot Desking
Guest In*93
Guest Out*093
Force Drop
Call Force Drop*94
Remote IVR
Remote IVR#9

SIP Settings

The SIP configurations require professional knowledge of SIP protocol, incorrect configuration may cause calling issues on the SIP extensions and SIP trunks.

Go to Settings > PBX > General > SIP to configure the SIP settings.

SIP General Settings

OptionDescription
UDP PortUDP Port used for SIP registrations. The default is 5060.
TCP PortTCP Port used for SIP registrations. The default is 5060.
Registration Timers
Max Registration TimeMaximum duration (in seconds) of incoming registrations and subscriptions. The default is 3600 seconds.
Min Registration TimeMinimum duration (in seconds) of incoming registration and subscriptions. The default is 60 seconds.
Qualify FrequencyHow often to send SIP OPTIONS packet to SIP device to check if the device is up. The default is 30 per second.
Outbound SIP Registrations
Registration AttemptsThe number of registration attempts before giving up (0 for no limit).
Default Incoming/Outgoing Registration Time

Default duration (in seconds) of incoming/outgoing registration. The default is 120 seconds.

Note: The actual duration needs to minus 10 seconds from the value you filled in.
Subscription Timer
Max Subscription TimeMaximum duration (in seconds) of incoming subscriptions. The default is 3600 seconds.
Min Subscription TimeMinimum duration (in seconds) of incoming subscriptions. The default is 90 seconds.

SIP Codec

A codec is a compression or decompression algorithm that used in the transmission of voice packets over a network or the Internet.Codec SelectionYeastar Cloud PBX supports G711 a-law, u-law, GSM, H261, H263, H263P, H264, SPEEX, G722, G726, ADPCM, G729A, MPEG4, opus and iLBC.Note:

  • You need to choose at least one same code on the PBX and on your phones, or there may be a problem of the call.
  • If you want to make video calls, you need to select H261, H263, H263P, H264 or MPEG4 codec on the PBX and on your phones.iLBC SettingsThe iLBC codec supports two modes: 20ms and 30ms frame length modes,To get better voice quality, you need to set the iLBC mode according to your SIP endpoints.Note: Linkus uses iLBC 20ms mode. When Linkus is enabled, this option is switched to 20ms mode automatically.

TLS Settings

OptionDescription
Enable TLSCheck the checkbox to enable TLS.
TLS PortTLS Port used for SIP registrations. The default is 5061.
TLS Client MethodSpecify protocol for outbound client connections. The default is sslv2.

Session Timer

A periodic refreshing of a SIP session that allows both the user agent and proxy to determine if the SIP session is still active.

OptionDescription
Session-timers

Choose the session timers mode on the system:

  • No: Do not include “timer” value in any field
  • Supported: Include “timer” value in Supported header
  • Require: Include “timer” value in Require header
  • Forced: Iclude “timer” value in both pportednd equired header.
The default is Supported.
Session-ExpiresThe max refresh interval in seconds.
Min-SEThe min refresh interval in seconds, it must not be less than 90.

Qos

QoS (Quality of Service) is a major issue in VoIP implementations. The issue is how to guarantee that packet traffic for a voice or other media connection will not be delayed or dropped due interference from other lower priority traffic.

When the network capacity is insufficient, QoS could provide priority to users by setting the value.

OptionDescription
ToS SIPType of Service for SIP packets.
ToS AudioType of Service for RTP audio packets.
ToS VideoType of Service for RTP video packets.
Cos SIPClass of Service for SIP packets.
Cos AudioClass of Service for RTP audio packets.
Cos VideoClass of Service for RTP video packets.

T.38

Adjust T.38 settings if T.38 Fax don't work.

OptionDescription
No T.38 Attributes in Re-invite SDPIf this option is selected, SDP re-invite packet will not contain T.38 attributes.
Error CorrectionEnable or disable Error Correction for the fax.
T.38 Max BitRateAdjust the max BitRate for T.38 fax.

Advanced SIP Settings

OptionDescription
User AgentChange the User-Agent field.
Send Remote Party IDWhether to send Remote-Party-ID in SIP header or not.
Note: This configuration only take effects on internal calls. To set up for external calls, configure the Advance settings of SIP trunk.
Send P Asserted IdentifyWhether to send P-Asserted-Identify in SIP header or not.
Note: This configuration only take effects on internal calls. To set up for external calls, configure the Advance settings of SIP trunk.
Send Diversion IDWhether to send Diversion in SIP header or not.

If this option is selected, the Diversion value will be extension number.

Note: This configuration only take effects on internal calls. To set up for external calls, configure the Advance settings of SIP trunk.
Support Early MediaWhether to support Early Media or not.
All Busy Mode for SIP Forking
  • Check this option: When one of the terminals that register the same extension number is busy in a call, the other terminals will not receive calls.
  • Uncheck this option: When one terminal is busy, the other terminals will still be able to make and receive calls.
Inband ProgressThis Inband Progress setting applies to all the extensions.
Note: To configure global Inband Progress setting, you need to contact Yeastar support to configure a custom config file.
  • Check this option: PBX will send a 183 Session Progress to the extension when told to indicate ringing and will immediately start sending ringing as audio.
  • Uncheck this option: PBX will send a 180 Ringing to the extension when told to indicate ringing and will NOT send it as audio.
Get Caller ID FromDecide the system will retrieve Caller ID from which header field.
Get DID FromDecide the system will retrieve DID from which header field.
Note: If Remote-Party-ID is selected but the SIP trunk doesn't support this, the system will retrieve DID fron INVITE header.
100relWhether to support 100rel or not.
Support Message RequestWhether to support SIP Message Request or not.
MaxptimeSelect or enter the Maxptime value.
Notify Caller IDIf checked, when extension A has an inbound call, PBX will send the call's Caller ID information to the extension that has subscribed to the A's call status. Displaying caller ID information can be useful to help an agent decide whether to pickup an incoming call. This option is disabled by default.
DTMF Passthrough

If DTMF Passthrough is enabled, PBX will not process the DMTF tones, and passe DTMF tones transparently to the other end.

Enable uaCSTA connectionIf this option is enabled, the PBX will use uaCSTA (User Agent Computer Supported Telecommunications Application) to remotely control the IP Phone via Linkus Desktop Client CTI. Your IP Phone needs to support uaCSTA standard to use this function.

Security

Restrict International Calls to Specific Countries and Regions

By default, users can place calls to any countries and regions. Yeastar Cloud PBX allows you to restrict users from making international calls to specific countries and regions.

Scenario

A manufacturer has a factory in Mexico, and his target customers are in Argentina. The manufacturer wants to set up a rule to restrict employees from making international calls to other countries.

Procedure

  1. Go to Settings > System > Security > Allowed Country Codes.
  2. In the Operation section, enable international dialing protection, and set international dialing code.
  3. Select the checkbox of Enable Allowed Country/Region Code Dialing Protection.Extension users can ONLY make international calls to the allowed countries or regions.
  4. In the International Dialing Code field, enter the international call prefix according to your country. In the scenario, enter 00.When a user tries to call a number starting with 00, the PBX's outbound route will identify this call as an international call, and then check if the country/region code is allowed.Note: Make sure there is at least one outbound route that matches with the international dialing code to route the international calls.
  5. Click Save.
  6. In the Country/Region Code Dial Management section, set users can make international calls to which countries or regions.
  1. In the search box, enter the desired countries or regions. In the scenario, enter Argentina.
  2. In the Allow column, turn on the option.In the scenario, users can NOT make international calls to countries/regions except Argentina.Note: Some countries or regions share the same code (e.g. The country code for Canada and America is 1 ). If you allow international dialing to a country/region, users can also place calls to the countries/regions that share the same code.

ResultWhen a user dials a number, PBX's outbound route will check if the dialing is valid:

  • If a user dials International Dialing Code + allowed Country/Region Code, the dial is considered as valid.
  • If a user dials International Dialing Code + disallowed Country/Region Code, the dial is considered as invalid.
  • If a user only dials Country/Region Code, the PBX will check if there is a matched outbound route to route the call out.

Blocked IP Address

The PBX will block an IP address for too many failed login attempts, too many failed registration attempts, or too many failed authentications for Auto Provisioning.

The blocked IP addresses would be listed in the Blocked IP Address table. If a trusted IP address was blocked by the PBX, you can go to Settings > System > Security > Access Control > Blocked IP Address to delete the IP address.

Service

All the PBX service statuses and ports are displayed on the security Service page.

Go to Settings > System > Security > Service to configure the service settings.

OptionDescription
Auto Logout Time (min)After the set time of inactivity, the session will automatically log out. The default time is 15 minutes.
SIP UDP PortSIP registration port. The default SIP UDP port is 5060.
Enable SIP TCPWhether to enable SIP TCP or not. The default port is 5060.
Enable SIP TLSWhether to enable SIP TLS or not. The default port is 5061.

Database Grant

Yeastar Cloud PBX is based on MySQL database. A third-party software can access the database of PBX. Grant permissions to database before accessing the database of PBX.

PrerequisitesDatabase Grant is associated with SBC, version requirements are as follows:

  • SBC version: 1.6.19 or later
  • PBX version: 81.14.0.67 or later

If Database Grant feature is not available after upgrade, contact your PBX provider.

Applications

By accessing the database of PBX, you can get CDR and save it to the local database.

Capture data in database

  1. Add database grant on PBX for the targeted device.
  2. Log in to the PBX web interface, go to Settings > System > Security > Database Grant.
  3. Select the checkbox of Enable Database Grant.
  4. Configure the settings:
  • Username: Enter the username that can be used by third party to access the database of PBX.
  • Password: Enter the password that can be used by third party to access the database of PBX.
  • Permitted IP/Subnet Mask: Enter the IP address or IP section that is allowed to access the database of PBX. The input format should be XXX.XXX.XXX.XXX.For example: 216.207.245.47 means that only the device with IP address 216.207.245.47 is allowed to access the database of PBX.
  1. Click Save and Apply.

You will get the Database Address and Port for database connection.

Access the database of PBX.

The following takes Navicat for MySQL for example to introduce how to access the database of PBX.

  1. Open Navicat for MySQL, click Connection, and select MySQL.
  2. Configure Navicat for MySQL with the authentication information provided on PBX.
  • Connection Name: Enter a connection name to help you identify it.
  • Host: Enter the Database Address of PBX.
  • Port: Enter the PBX port 12000.
  • User Name: Enter the user name configured on Database Grant of PBX.
  • Password: Enter the password configured on Database Grant of PBX.
  1. Click Test Connection to make sure that the connection is successful, and then click OK.
  2. Click cdr table, you can see existing cdr tables on PBX
  3. Note: The database generates a cdr table every month.

CDR Parameters in Database

Descriptions for CDR parameters in the database of PBX.

Description of CDR Parameters

ParametersDescriptions
idNo special meaning, all ids are 0.
datetimeDate and time
clidCaller Name<Extension>
srcCaller Number
dstCalled Number
dcontextDial plan
srctrunkSource trunk
dstrunkDestination trunk
lastappThe last operation of the extension
lastdataSystem internal flag
durationTalk duration (calculates from the beginning of the call)
billableBilling duration
dispositionAnswered status of the call
amaflagsSystem internal flag
calltypeCall type:
  • Internal
  • Inbound
  • Outbound
  • Transfer
accountcodeBilling password
uniqueidCDR unique identifier
recordfileRecordings name
recordpathRecordings path (with file name)
monitorfileName of One Touch Recordings
monitorpathPath of One Touch Recordings (with file name)
dstmonitorfileName of One Touch Recordings for callee
dstmonitorpathPath of One Touch Recordings for callee
extfield1Caller name
extfield2Callee name
extfield3The displayed DOD number when the caller makes an outbound call.
extfield4IP address of the phone
extfield5The phone number displayed (without patterns of outbound routes) when the caller makes an outbound call.
payaccountThe account which will be charged.
usercostCall cost that the extension should afford.
didnumberDID number that the caller dials.
transbillingSystem internal flag
payextenThe extension which will be charged.
srcchanurlSystem internal flag
dstchanurlSystem internal flag

Asterisk Manager Interface (AMI)

The Asterisk Manager Interface (AMI) is a system monitoring and management interface provided by Asterisk. Yeastar Cloud PBX supports AMI that allows you to connect an AMI client to Yeastar Cloud PBX.

What is Asterisk Manager Interface (AMI)

Asterisk Manager Interface(AMI) is a standard management interface into Asterisk server. It is a client/server model over TCP that allows a client program to connect to an Asterisk server and issue commands or read events over a TCP/IP stream. With the manager interface, you can control the PBX, originate calls, check mailbox status, monitor extensions and so on.

Connect an AMI client to Yeastar Cloud PBX

  1. Enable AMI on PBX.
  2. Log in to the PBX web interface, go to Settings > System > Security > Service.
  3. Select the checkbox of Enable AMI.
  4. Configure the connection authentication.
  • Username: Enter the username that can be used by third party to access the AMI of PBX.
  • Password: Enter the password that can be used by third party to access the AMI of PBX.
  • Permitted IP/Subnet Mask: Enter the IP address or IP section that is allowed to access the AMI of PBX. The input format should be XXX.XXX.XXX.XXX.

For example: 216.207.245.47 means that only the device with IP address 216.207.245.47 is allowed to access the AMI of PBX.

Click Save and Apply.

You will get the Service Address and Port for AMI connection.

  1. Configure AMI client with the authentication information provided on PBX, and connect client to PBX.

User Permission

By default, the extension users can log in the system and check their own settings and CDR. You can set different permission to the users according to their roles and duty.

User Types on the PBXSuper Admin

Super Admin has the highest privilege. The super administrator can access all pages on S-Series Web and make all the configurations on the system.

  • Username: admin

Administrator or Custom UserAdministrator or Custom User is created by the Super Admin. The Super Admin sets the privileges for those users according to their roles and duty.

  • Username: The email address of the extension user.Note:
  • Administrator and Custom User can have the same permission. The different between the two role type:
  • Administrator: All permissions are enabled by default.
  • Custom User: No permission is enabled by default.
  • Administrator and Custom User do not have permission to configure User Permission.

Configure User Permission

To grand more privilege for a user or change the user's privilege, you need to configure the User Permission on PBX.

Scenarios

In the following scenarios, you may need to add permissions for the extension users according to their roles.

  • For an HR, he/she may need the permission to add extension, configure extension's outbound route privilege when there are new staffs.
  • For a supervisor, he/she will have permission to check the CDR and recordings, and have no permission to configure the system or other extensions.

Procedures

  1. Log in the PBX web interface by the super admin account, go to Settings > System > User Permission, click Add.
  2. On the configuration page, select the User.
  3. Set the Set Privilege As.
  • Administrator: All the permissions are enabled for the user by default.
  • Custom User: No permission is enabled for the user by default.
  1. Click the Settings, CDR and Recordings, Monitor, Application, Contacts, and Others tabs, and check or uncheck the relevant options for the user.
  2. Click Save and Apply.Results: When the user logs in the PBX web interface by the extension user account, he/she can access the permitted configuration page.

Date and Time

To ensure that the time of logs and CDR is consistent with your local time , you need to adjust the date and time of the PBX.

On the Date & Time configuration page, you can see the current time of the PBX.

You can set the PBX time to be synchronized with a NTP server or set the time manually.

Change the PBX Time

  1. Go to Settings > System > Date & Time.
  2. Select your current and correct Time Zone.
  3. Check the option Daylight Saving Time if you need it in your place.
  4. Select Set Up Manually and set the Date and Time according to your local time.
  5. Click Save.
  6. Reboot the PBX to take effect.

Email

The system email can be used to reset password, send voicemail to email, send alert event emails, and send fax to email. To make these features work, you need to set up the PBX system email.

Set up System Email

  1. Go to Settings > System > Email to set up the system email.
  • Sender Email Address: Enter an available email address.
  • Email Address or Username: If the email server supports for User Name, enter user name. If not,enter the email address.
  • Password: Enter the login password of the email address.
  • Outgoing Mail Server (SMTP): Enter the outgoing mail server and port according to the email server.
  • Incoming Mail Server (POP3): Enter the incoming mail server and port according to the email server.
  • Enable TLS: Enable or disable TLS during transferring/submitting your Email to another SMTP server.Note: For Gmail or Exchange server, you need to enable TLS.
  • STARTTLS: If you enable TLS, the STARTTLS is enabled by default . If the mail server doesn't support STARTTLS, do not select this option.
  1. Click Test to check if the email works.
  2. Click Save to save the email settings.

Change Email Notification Language

Yeastar Cloud PBX supports two email notification languages: English and Chinese Simplified. This topic describes how to change email notification language.

Procedure

  1. Log in to the PBX web interface, go to Settings > System > Email > Email Templates, click Notification Email Language
  2. In the Language drop-down list, select a desired language.

Result

All email templates will be changed to the specified language.

Auto Cleanup

Auto Cleanup is a feature that can auto clean your CDR, logs, voicemails, one-touch recordings periodically.

CDR Auto Cleanup
Max Number of CDRSet the maximum number of CDR that should be retained. The old CDR will be deleted when the threshold is reached.
CDR Preservation DurationSet the maximum number of days that CDR should be retained.
Voicemail and One Touch Recording Auto Cleanup
Max Number of FilesSet the maximum number of voicemail and one touch recording files that should be retained. The old CDR will be deleted when the threshold is reached.
Files Preservation DurationSet the maximum number of minutes that voicemails and one touch recordings should be retained.
Logs Auto Cleanup
Max Size of Total LogsLimit the total size of pbxlog files in syslog.

The old logs will be deleted when the threshold is reached.

Logs Preservation Duration

Set the maximum number of days that system logs should be retained respectively.

Max Number of Logs

Set the maximum number of event logs and operation logs that should be retained. The old logs will be deleted when the threshold is reached.

Event Center

Yeastar Cloud PBX can monitor system events and logs, then send notifications to the specified notification contacts.

Event types

Yeastar Cloud PBX events are divided into three major categories: operation, telephony, and system.

CategoryEvent Type
Operation
  • Modify Administrator Password
  • User Login Success
  • User Login Failed
  • User Lockout
  • API Authentication Lockout
  • Extension User Password Changed
  • RPS Request Success
  • RPS Request Failed
  • Linkus Client Login Failure
  • Linkus Client has been Locked
Telephony
  • VoIP Peer Trunk Registration Failed
  • VoIP Register Trunk Registration Failed
  • Outgoing Call Failed
  • Concurrent Calls Overload
  • Emergency Call
  • Extension Outbound Calls Prohibited
  • Modify the Port of Peer Trunk
  • VoIP Peer Trunk Re-registered
  • VoIP Register Trunk Re-registered
System
  • Storage Full
  • Network Attacked
  • System Reboot
  • System Upgrade
  • System Restore
  • Application Upgrade
  • Auto Cleanup Reminder - CDR
  • Application New Version Detection
  • System New Firmware Detection
  • Auto Cleanup Reminder - Auto Recordings

Event Settings

Go to Settings > Event Center > Event Settings to decide whether to record or monitor the events.

  • Record

indicates that Record function is enabled. When the event occurs, the PBX will record the event in Event Log.

indicates that Record function is disabled.

  • Notification

indicates that Notification function is enabled. When the event occurs, the PBX will send notification to the Notification Contacts.

indicates that Notification function is disabled.

  • Edit NotificationClick

to edit the template of notification email.

Event Log

Event log records of what you select in Event Settings. With the event logs you can check all the event details easily.

You can filter the event logs by selecting an event type, event name, and specifying a certain time period.

Add Notification Contacts

You can set the PBX to send notifications when specific events or errors occur, notifying you via email, extensions, or mobile devices.

  1. Go to Settings > Event Center > Notification Contacts, click Add.
  2. On the configuration page, choose a contact and set the notification method.
  • Choose Contact: Choose an extension user or choose Custom to add an external contact.
  • Notification Method: Select how to notify the contact when the event occurs.
  • Email: The PBX will send notifications to the email address of the contact.
  • Call Extension: The PBX will call the extension number of the contact when the event occurs.
  • Call Mobile: The PBX will call the mobile number of the contact when the event occurs.
  • Email: If you choose Notification Mode to Email, you need to set the email address of the contact.
  • Mobile Number: If you choose Notification Method to Call Mobile, you need to set the mobile number of the contact and set the Prefix according to the outbound route pattern on the PBX.
  1. Click Save and Apply.

Remote Management

Yeastar Remote Management provides an affordable, low maintenance solution for easily deploying Yeastar VoIP PBX and VoIP gateways across multiple locations, reducing complexity and providing deep visibility and control.

Compatibility

The following Yeastar products supports Remote Management feature:

  • Yeastar Cloud PBX: 81.4.0.X or later
  • Yeastar S-Series VoIP PBX: 30.6.0.20 or later
  • Yeastar TA1600/TA2400/TA3200 V3

Remote Management Guide

How to manage Yeastar products on the Remote Management platform, refer to the Remote Management Guide.

API

Yeastar Cloud PBX provides API interfaces for you to integrate a third-party software or device.

Compatibility

API feature is supported on Yeastar Cloud PBX v81.4.0.8 or later.

API Guide

For more information of API, refer to Yeastar Cloud PBX- API guide.

In the API guide, we introduces how to enable and configure API on Yeastar Cloud PBX, and provides API references.