True digital sound in GSM-cards for Asterisk

 True digital sound in GSM-cards for Asterisk

New GSM-cards for Asterisk (with support for WCDMA/UMTS) are now capable of digital sound processing. This improvement provides higher quality of speech, clear sound with no interferences or noises. Technically, it means the sound from radio-module sent to the system already in digital form i.e. the sound already digitized by the module itself.


It is still possible to switch to analogue sound mode by sending special AT-command to each radio-module from Asterisk console. Switching to digital sound currently supported only by cards with the support of WCDMA/UMTS, but they still can be used in regular GSM-networks (without UMTS).

New API-command “callStatus” for anti-fraud solution based on SIM-server Polygator

New API-command ~callStatus~ for anti-fraud solution based on SIM-server Polygator

The external API of SIM-server Polygator is based on json technology. The API is constantly under development. Recently it is updated with new command: callStatus. This command enables the user to fine-tune SIM-card behavior based on its call-stage with more precision and integrate SIM-server with any external software. It is useful for optimizing activation, monitoring and rotation tasks, etc. To read more about API-commands you can request list of features, DOCs and demo-access.



Any anti-fraud system is based on knowledge of mobile operator fraud-machine methods. This knowledge can be obtained on own experience or “professional advice”, but this information can not be actual forever. Operator change and update rules all the time that is why the main feature of your SIM-server should be flexibility.



SIM-server Polygator provides an unique level of flexibility to fine-tune system and match mobile operator rules. You can control allowed time for SIM-card per day, number of calls. It is also possible to change IMEI codes and generate incoming calls inside “family”. Besides, the equipment allows to automatically rotate SIM-cards, base stations, remove SIM-cards from rotation on “balance low” and on “blocked” events. Also, it can simulate user action like balance checking, Internet access, SMS-ing to “friends” (constant group of contacts) and many more other features.


GSM-combiner (splitter) for 8 and 32 channels (for 19" rack)


GSM-combiner (splitter) allows to reduce the number of GSM-gateway antennas and to provide GSM-signal in areas with weak mobile network coverage. When GSM-gateway placed in server room or in basement it often results in low GSM-signal levels. GSM-combiner with the feeder is the only simple way to provide the device with GSM-signal in such areas. For example, by using combiner and external antenna with feeder of 10-20 meters paced on the roof or external wall of the building you have more chances to supply high signal levels to the GSM-device.

GSM-combiners are available in 8-channel and 32-channel designs. 32-channel model has 19"-rack compatible housing. The splitter is equipped with SMA-connectors and supplied with patch-cords, feeder 10 m and YAGI-antenna. Feeder length can be adjusted individually on order.




SIM-server “human emulation” feature: Internet-surfing via GPRS/3G

SIM-server “human emulation” feature: Internet-surfing via GPRS/3G

SIM-server Polygator software interface allows to setup SIM-cards “human emulation” for surfing the Internet. SIM-card can go to Internet “occasionally” from time to time via GPRS or 3G-connection. The connection type is defined automatically and solely depends on network type (GSM, UMTS) the SIM-card currently registered to.


System setup options allow to define the frequency of Internet surfing and to define a list of websites which will be visited by SIM-card “owner”. This feature is good to use together with other functions of “human emulation” like cross-calling and cross-smsing inside «family» and switching between Base Stations.

Our article on habrahabr about development of board for GSM-gateway

Our article on habrahabr about development of board for GSM-gateway

GSM-gateways and other “Polygator” equipment are result of own research and development done by our company. You may have a look at this article (Russian language) about how the development of the CPU-board is performed. This board is present in the GSM-gateways of G20 and G8 series. (rus)

VoIP-GSM gateways G20/G8-series support GSM and UMTS (optional) networks, as well as they can be equipped with PRI, FXO and FXS ports thanks to modular architecture. This way you may have any telecommunication technologies together in this device. Besides, the device is based on Linux OS and ARM-processor capable of running Asterisk (universal IP-PBX, OpenVPN (VPN-network client), Kannel (SMS-server and other handy software «on board» for implementing extremely portable and cost-efficient solutions.

Product page

Polygator G20


Polygator G8


Controllable switching between BTS by the GSM-gateway

gsm-gateway-base station_switch

GSM-gateways Polygator allow to setup special mode of interaction between the GSM-gateways and Base Transceiver Station (BTS). For example, there is special mode for switching automatically between visible 6 base stations on certain conditions.

Switching among BTS is performed during pauses between voice calls. Frequency of BTS switching is set by randomized time bounds. Besides, some of visible base stations can be excluded from the list. The list is available on the web-interface of GSM-gateway and accompanied with some additional information. Operation mode and base stations list can be set up for each GSM-module individually.

10-card SIM-holders for easy SIM-bank loading

10-card SIM-holders for easy SIM-bank loading

Huge number and frequent rotation of SIM-cards makes it necessary to load SIM-bank with “fresh” cards fast. In order to replace several cards it is enough to remove them from the SIM-holders directly and it does not required to stop whole system or to remove any parts. The same way you can replace the whole SIM-holders with 10 SIM-cards by replacing it with another one. If you need to replace quickly 100 or 200 SIM-cards – you can prepare in advance 10 or 20 holders filled with SIM-cards. You can replace filled old holders with filled new ones. It allows to cut time for "reloading" of system many times.


The design of SIM-bank Polygator provides maximal flexibility no matter if you deal with big number of SIM-cards or with single cards. The advantage of such approach is the easy reserving of SIM-cards and fast SIM-bank loading. In order to remove or to insert the whole SIM-holders in the bank it is not necessary to make power off or remove any parts of the equipment.

SMS-gateways Polygator – universal solutions for SMS, USSD, STK and QoS


Polygator GSM-equipment is capable of performing tasks not only for voice telephony but also for establishing full-scale SMS-solutions. By using GSM-gateways or GSM-cards it is possible to perform bulk SMS-sending and receiving of SMS in GSM and UMTS networks, execute USSD-requests and perform testing of mobile network services quality.

It is possible to integrate device in any system by protocols HTTP, SMPP, Email-SMS, AT-commands via TCP/IP directly to the GSM-modems and others. By using GSM-cards Polygator under IP-PBX Asterisk it is possible to work with SMS via SQLLite database or dialplan. In order to use the Gateway as QoS probe it is possible to setup custom script execution on each event. The script can be written on any scripting language supported by Linux Shell and will be executed each time event detected by software. For example, the system can perform HTTP-request to remote server each time SMS or Call received. Such HTTP-request may include additional information like caller number, IMSI of receiving SIM-card, data about BS and additional timing information.

2gsm-board-8ch copy

For creating big-scale systems it is worth to consider the use of SMS-gateways with SIM-banks and SIM-server software. By using a SIM-bank you can save time on processing hundreds of SIM-cards, automatically perform SIM-card activation and using cheap SMS-plans. The system will automatically rotate SIM-cards in GSM-gateways in order to keep constant service availability. Additionally, Polygator SIM-server software can be controlled by external systems via an API.


“Сall-clipping” feature of the GSM-board for Asterisk


When using GSM-gateways it often happen, you call somebody and get no immediate reply. Shortly, the subscriber calls back to missed call number (GSM-gateway number) and reach unfamiliar call-center operator or unfamiliar office worker. It brings disappointment and additional time expenses on both sides.

Multichannel PCI-board Polygator for Asterisk helps to avoid such situation by implementing Call-clipping feature. The feature allows to remember pairs of numbers (caller and called) and check the incoming number against “caller-called” pairs in the database. If found – the Asterisk module will connect calling people to the found operator SIP-number. GSM-card module settings allow defining for how long this information is stored in the database.

GSM-card product page.

The GSM-card is certified according to Elastix Hardware Certification Program (EHCP) for usage with Elastix ( Link to the list of certified hardware.



Wi-Fi USB-dongle is supported by VoIP-FXS gateway for 40 channels


If you need to connect FXS gateway Polygator to network, but you do not have cable in the right place you still can use Wi-Fi. By installing Wi-Fi USB-dongle in one of the USB-slots, you can immediately have the device working in wireless networks.

VoIP-FXS gateway Polygator can be equipped with up to 40 FXS-channels, as well as with FXO-ports, GSM-ports and UMTS/GSM-ports for direct inserting of SIM-cards or using remote SIM-bank. Pre-installed IP-PBX “Asterisk” can be optionally engaged in telephony tasks as standalone mini-PBX.


Contact Details

POLYGATOR (manufacturer)

This email address is being protected from spambots. You need JavaScript enabled to view it.



+380(56)719-9030 (Office Landline)
+380(67)527-4171 (Mob/Telegram)

UK+44(203)769-1858 (Virt.Landline)

USA+1(312)940-6939 (Virt.Landline)

Compatibility Short-list

Native drivers Certified with Tested with Technologies
(PCI GSM Interface Card for 4/8 SIM-cards)


SoftSwitch, IP-PBX

VoIP Billing

SMS software



G.729 G.711 G.723 G.726 DTMF

SMS protocols
SMPP SMTP AT-commands SMS-via-SQLLite (Under Asterisk)

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