SIP Wireless WAN in Zambia

Brekeke PBX


Efficient, clear, reliable communication is a key component of modern life. However there are many places around that globe that have yet to develop the infrastructure many of us rely upon to make this a possibility. Brekeke’s technology facilitates the creation of SIP communications efficiently and affordably, without needing to rely upon outdated or potentially nonexistent infrastructure.

In the case of The Center for Infectious Disease Research in Zambia, Brekeke solutions are helping to connect nearly 30 medical sites dispersed throughout the region with the main hospital in Lusaka, facilitating a degree of communication and collaboration amongst medical staff—both on the research and service side of the organization—that was previously impossible.

SIP Wireless WAN System Diagram - Network Structure


Client: The Center for Infectious Disease Research in Zambia (CIDRZ
Location: Zambia
Product: Brekeke PBX
Number of sites: 28 Locations

The Center for Infectious Disease Research in Zambia (CIDRZ) is a nonprofit organization established in 1999 with the support from the University of Alabama at Birmingham, USA. Initially conceived as an infectious disease and maternal-child health research unit, CIDRZ has since expanded its operations to include support to the Zambian government in its fight against AIDS.

CIDRZ operates a wireless Wide area Network connecting its four facilities, LAB and 24 geographically dispersed health clinics with the main hospital in Lusaka. The basic layout of the network is 45Mbps point to point links interconnecting high sites that form the backbone, and 36Mbps point to multipoint links to participating health centers and clinics. The Proxim Tsunami WAN equipment operates in 5.8 GHz band for the network backbone and last mile connection to the centers. All participating centers are equipped with a Tsunami subscriber unit capable of providing a maximum throughput of 36Mbps and terminating internally on a 100MBps switch.

All the clinic's networks and most of the equipment installed at the hospital are wireless. 802.11b was chosen as a standard, due to its market penetration and interoperability, (with clear upgrade path to 802.11g in future). The main requirement of computers and laptops in the clinics is mobility hence implementing the wireless Local Area Network (LAN) using CISCO Aironet 1240 with external Omni directional antennae covering an estimated 200 to 300 meter radius foot print.


Voice communication services are a priority for clinics and health centers, which often deal with life-and-death situations. In these situations, clinicians such as midwives, nurses and physicians are able to fully express the problem being experienced, and receive real-time advice from specialists in larger hospitals. VoIP has been implemented across the organization, the benefits of which include lower costs and a richer phone terminal feature set. The Brekeke PBX solution will help provide the medical staff, both on the research and service side of the organization, to effectively communicate and collaborate.

The objective of this solution is to ensure that an employee connected to the Wide Area Network is able to place voice calls regardless of location or terminal type. We intend to connect soft phones, PBX extensions, MultiTech VoIP extensions, PSTN lines and mobile phones to the Brekeke PBX.

  1. Integrating the software PBX with an existing Toshiba hardware legacy PBX
  2. Integrating the software PBX with existing MultiTech VoIP solution
  3. Choosing the right Codec for a soft phone installed on PCs and enabling echo cancellation
  4. Registering MultiTech VoIP Gateways clients with Brekeke SIP server
  5. NAT traversal


  1. Installed Brekeke PBX v. Pro Edition
  2. Installed 3CX soft phones to use G.711 u-law, 64kbit/s on PCs and Laptops on different location on the Network
  3. Configured MultiTech VoIP Gateways to register with the Brekeke SIP Server
  4. Integrated MultiTech VoIP gateway with the Toshiba legacy PBX
  5. Configured a STUN server for NAT traversal
  6. Configured Linksys Wireless-G IP Phone to register with Brekeke PBX

Result and Benefits:

When one initiates a call from a soft phone to another soft phone the communication is established through Brekeke PBX and if there is no answer for about 30 seconds the Brekeke PBX does forward the call to the next numbers separated by commas programmed in call forwarding settings options of Brekeke PBX. In our case the next number is PBX extension which we defined in ARS and dial plan option of Brekeke PBX. The call gets to the corresponding registered VoIP gateway client also connected to the PBX through an FXO/FXS interface and initiates a call to the PBX extension. After 30 seconds of no answer from the PBX extension the call is forwarded to the next number in the sequence in forwarding settings options in our case it's a Linksys wireless-G IP phone so long as it's in the range of the foot print covered by the access point. The next number in the sequence if there is no answer or the extension is busy is the mobile phone number which goes through the registered VoIP gateway connected to the PBX to the mobile service provider and lastly the PSTN number which also goes through the same channel as the mobile number. The Brekeke PBX is also configured to send Voice mail messages in the form of emails to individual email addresses in case someone needs to leave a voice message.

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