1493284664645476.jpg +86 075561882266    1493284683105363.jpg  +852 21357223 


Home > Solutions


    Asterisk Development” We have expertise in Asterisk Installation, Support, Up-gradation & Maintenance. ” Asterisk is a free and open source framework for building communications applications.

    1. Detail info

    Asterisk-based Phone System Solution


    1. Solution background

    With the rapid development of IP technology represented by Internet, IP network has been used widely. In order to further promote the process of information construction, improve work efficiency and create more social and economic benefits, many government agencies, large and medium-sized enterprises have begun to build internal IP-PBX. For industry and enterprise users, IP-PBX technology can also bring a huge change to enterprise communication and provide industry and business users with a new enterprise communication system featuring high efficiency, low cost and  low royalty.

    Phone has already been a major communication means in and among enterprises. Long-distance call charge is an important expense of a company. If an enterprise wants to do some other businesses via phone, it will bear the call charge. VoIP can help an enterprise save the cost and improve staff’s work efficiency. VoIP and IPPBX can achieve basic voice services, long-distance bypass and complex value-added services. Therefore, it has become a cost-effective choice for an enterprise. This solution will serve as a typical case for an enterprise to display its outbound service.

    2. System functions and features

    Cost reduction: VoIP does not use the circuit switching network again, which saves the long-distance call charge per minute. Users’ monthly Internet charge is maintained at a low level. VoIP also combines voice and data network to make full use of existing IP bandwidth and reduce the cost of central office devices.

    Simple, powerful and reliable: If a device supports voice and data communication, it will realize a simple and convenient central office device design. The integrated network can also realize dynamic bandwidth optimization and fault-tolerant design.

    Advanced applications: As VoIP adopts the compressed and packeted digital format, its potential in advanced multimedia and multi-service applications is unlimited, including applications in Web-enabled call center, collaborative whiteboard, remote communication switching, personal work efficiency improvement (such as unified message handling), etc.

    The more branches of an enterprise or organization or its partners, the more necessary the communication between departments. The more scattered the branches of an enterprise are, the more phone numbers it announces. Its customers will be at loose ends. Moreover, most enterprises set up their branches in different regions, which have different division of labor and advantages. How to strengthen the internal humanized communication among various departments of an enterprises or organization? How to make customers feel that the enterprise is an organization which is orderly and easy to communicate rather than scattered and difficult to communicate? How to make use of different backgrounds and advantages in different regions? These issues are most concerned by the enterprise management agencies.

    3. Solution

    Demand analysis

    Our company has a total of 12 outside lines and more than 100 extensions. Asterisk is used to realize all the functions available to a general switchboard, such as call forwarding, message mailbox and direct incoming call of VIPs.

    12 outside lines are connected from PSTN and defined respectively as 66666661-66666672. Our company has more than 100 extensions which are defined as 1101-1200. Some functions can be realized through Asterisk. More diverse functions can be realized by to connect it to PSTN with the board. In this way, we can provide a lot of value-added services, such as call forwarding, voice messages, unconditional forwarding, switchboard, teleconference, etc.


    Topological diagram



    It can be seen from the above diagram that 12 analog lines are connected to PSTN. There are more than 100 internal extensions, including three kinds of extensions: soft phones, IP phone and analog phones.

    4. Functions

    • Unified switchboard: The headquarters or branches can use the same switchboard number, which is good for improving our company’s image and unify the management.

    • Automatic and manual console: Company’s welcome message can be customized by recording. Different voice prompts can be given between working hours and off-duty time. Direct connection with manual switchboard can be set for personnel to answer the phone.

    • Extension direct dialing: The extension numbers can be directly dialed between Guangzhou headquarters and branches, which will save long-distance call charge and prevent work efficiency from being affected due to busy switchboard.

    • Long-distance bypass: Phone charge can be saved, and users can set their own dialing rules, including abbreviated dialing, user dialing habit setting, etc.

    • Call waiting / retrieve: When both parties are in a normal call, either party can stop the call via the Hold key and the other party will hear the Hold music. If the party that launches Hold wants to retrieve the normal call, he can press the Retrieve key. This is applicable to such a scenario that either party wants to search for information or discuss with other people.

    • Number follow-up (one number): An extension number can be forwarded to another extension, fixed phone, mobile phone, message box and so on to realize one-number function. This will make contact possible and will not divulge any privacy number.

    • Call barring: Call barring is mainly used to limit the outgoing calls of some users, such as local call restriction, DDD, IDD, etc. An enterprise can effectively control long-distance phone charges by limiting the prefixes of the called numbers. Call barring can be configured for each user or device.

    • Call permission: Call permission is mainly used to limit users’ call authority. For example, if users are only allowed to have local calls, they can only dial the called numbers compliant with the configuration rules by adding some prefixes to the called numbers to limit their outgoing calls. Call permission can be configured for each user or device. The soft switch system operator may decide whether to open this service to users.

    • Direct inward dialing (DID): When an extension is set to the DID of a direct number, when an external phone calls the outside line number, the system will directly call the extension to realize extension direct dialing.

    • Call forwarding: Call forwarding is divided into four types: call forwarding unconditional (CFU), call forwarding busy (CFB), call forwarding no reply (CFNRY) and call forwarding offline (CFO).

    • CFU: When CFU is used, all the calls will be automatically forwarded to the user’s preset number no matter what state the called user is.

    • CFB: When CFB is used, all the calls will be automatically forwarded to the user’s preset number if the called is busy.

    • CFNRY: When CFNRY is used, all the calls will be automatically forwarded to the user’s preset number if the called is in a no-answer response for a long time.

    • CFO: When CFO is used, all the calls will be automatically forwarded to the user’s preset number if the called uses an IP device and its current state is offline.

    • Group ringing: The extensions of relevant personnel with the same task are set to the same group. When a call comes, the idle extensions in the group will ring until any one of them is picked up. It is applicable to customer service technical support hotline and other scenarios.

    • Cycle ringing: The extensions of relevant personnel with the same task are set to the same group. When a call comes, the idle extensions in the group will ring until any one of them is picked up. Other extensions stop ringing. It is applicable to customer service technical support hotline and other scenarios.

    • Distinctive ringing: The extensions in the enterprise can distinguish the ringing between external call and internal call. Extensions are equipped to distinguish the ringing. You may select different ringtones for inside and outside lines.


    1. Strong networking adaptability

    The implementation of the system is not limited by the actual networking of an enterprise. There is no need to adjust the data network (such as address redeployment, network domain adjustment, etc.). It can help unify automatic switchboard and IVR, improve corporate image and accelerate the process of enterprise informatization. If IP network has a failure, we can use PSTN without affecting the use.

    2. Low network investment cost

    Enterprise only needs to build and maintain a set of IP data network to provide voice, data, video, teleconference and other media communication services. Internal dialing is free of charge. Long-distance call uses IP network to save the charges.

    3. Low engineering construction cost

    Engineering construction is simple. Except the server system adopted in the headquarters, only simple plugging operation is required when other branches and offices are connected with network phone system. Each point is only equipped with a high integrated user gateway device.

    4. Multiple access modes integrating enterprise’s phone systems

    Regardless of whether the headquarters and branches have a PBX system or how many phones they have, the solution can provide diverse access solutions to meet different demands of an enterprise. The system can be connected with soft phone, ordinary phone and IP phone, featuring easy installation and convenient use.

    5. Unified planning of phone number and voice communication

    Our solution can help an enterprise plan its internal phone numbers, such as mutual dialing of short numbers in the enterprise.

    6. Dialing habit unchanged

    The original dialing habit of enterprise and users is not changed at all.

    7. Centralized management and easy maintenance

    Maintenance can be done easily through convenient and flexible management tools

    8. Diverse service functions

    An enterprise can enjoy the special expensive services from the call center.

    9. Protocol and coding support

    VoIP protocol supported

    · SIP protocol: Support SIP2.0 (RFC3261) version

    · H323 protocol: Support H.323 V2, V3, V4 version

    · IAX2 protocol

    Voice coding supported

    · G.729: Support call and IVR playback

    · G.723.1: Support call and IVR playback

    · G.711: support G.711μ law and G.711a law. Support call and IVR playback

    · GSM

    Video encoding supported

    · Support H.263 video encoding, not forward video media stream

    · Support DTMF formats

    · Support in-band DTMF (RFC2833) and out-of-band DTMF, secondary dialing and other operations. If an extension number is entered under IVR instructions or an automated service is entered like phone banking, you can conduct secondary dialing according to the prompt.