Communications Recording

General Introduction

The CRU-2AN is a small sized, IP based, two-channel voice recording system with two symmetrical analogue line inputs and two microphone inputs. CRU-2AN is designed for recording the voice communication of TETRA DWS, but it also can be used as a general voice recorder in wide area. With an optional cable, which can be connected to TMR880 desktop radio handset’s front connector it also can record the TMR880’s voice communication (if recording of call related information and SDS messages is required see our CRU-1 product in the TETRA APPS). Using the CRU2-AN’s microphone inputs beside the DWS voice recording the voice surveillance of the dispatcher's room is also possible.

The device works at exceptionally low power (<1W) and can record of the voice communication of two DWSs simultaneously because the CRU2-AN has two separated logical voice recorders. As a special feature the equipment can be configured as a stereo voice recorder and can record the two directions of a call into a stereo file as left/right channels.
Analogue Recorder

The CRU-2AN can be configured and set up by its client application (CRU-2AN-PC software). This client application can run under WINDOWS 2000/WINDOWS10 on any Pentium 4 and above (or on of >1GHz Pentium 3) configuration. No special requirements are needed..

Operation Details

There are two available basic types of recording:

  • On one hand, the CRU-2AN can record using its SD cards independently. The applied file system is FAT32, so removing the SD cards and inserting them into a card reader the records can easily be carried for a PC and can be copied and listened under WINDOWS. The device automatically selects the available card, so it is possible to remove a full SD card while the other one is active.
  • On the other direct recording on the PC’s HDD is also possible with the client application. Furthermore, parallel recording on the CRU-2AN’s SD card and on the client PC’s HDD can also be set up. With the client application the inputs can be listened in real-time (independently from the recording).
The recorded files can be played back with the client application. Two types of playback are possible: local or remote. Local playback can be used to play the records stored on the PC’s HDD or stored on the inserted SD card. Remote playback is used when the SD card is not removed from the CRU-2AN. In this case the files can be played through the IP connection. The playback does not disturb the existing recording (simultaneous recording and playback on the SD card).

In the client application the current status of the SD cards are shown: active recordings, number of records, available free space, SD card operation status, etc.

The recording can be continuous, or VOX triggered. A highly efficient adaptive voice detector is implemented for both channels.

On the SD card circle recording can be set up. In this case the device handles the two SD card like one storage, and in case of full SD cards the oldest files are deleted automatically.

Audio file format, Protection

The audio data is stored in a vendor specific encrypted and electronically signed format. The files can be carried and copied under windows with the file manager because the files are standard FAT32 files. The content is specific and is protected with electronic sign. The playback is possible with the client application. The client application verifies the electronic sign and decodes the applied encryption. From the client application all the files can be exported into standard “wave” files and after this, files can be played with a standard media player.

On demand, the format on the SD card can be changed into standard WAVE format. In this case the records on a removed SD cards can be listened without any client program activity. No additional client program is required (only for set up). The configuration is stored in the CRU’s flash memory).

The exact time stamps of the start and the end date/time of a speech communication (VOX trigger begin/end) are attached inseparably to the speech content.

Other technical parameters

  • Two microphone input with 0-50dB adjustable gain and +30dB selectable with jumper.
  • Two symmetrical (balanced) line inputs towards DWS recording output or other audio sources. Maximum acceptable level is +6dBm. 0-50dB adjustable gain can be applied.
  • Independent automatic gain controls for both channels.
  • Two independent voice activity detectors
  • Selectable sampling frequency (8KHz, 16KHz, 24KHz), 8KHz is recommended for DWS recording.
  • 1x stereo or 2x mono operation modes.
  • Low power consumption (<1W).
  • Applicable SD cards: 1GB, 2GB SD, 4GB, 8GB, 16GB SDHC or Ultra II cards
  • Interoperation with HUNGAROCOM’s centralized archive recording system (optional).
High storage capacity: with two 16GB micro SDHC card and with 8KHz sampling frequency the capacity is about 45-day continuous speech.

Analogue Recorder
client application
General Introduction

Hungarocom's CYPCOM equipment family can offer different functions on, or between E1 and IP lines like bridge, media converter, E1 over IP, IP over E1, with encryption and different monitoring recording functions. These functions are based on two types of application specific core hardware units:
  • CYPCOM-200 hardware has eight Ethernet interfaces and two E1 PCM interfaces (RJ-45)
  • CYPCOM-201 hardware has two Ethernet interfaces and four E1 PCM interfaces (RJ-45)
The common parameters of both versions are: 230V or 48V (12V optional) operation, 1 unit high standard rack construction, high protected equipment box with key (no screws outside), high speed low power consumption core module, upgradable firmware, physical alarm contacts. There are 75/120 ohm or high impedance E1 connections. Central remote management is available for all applications. Based on these flexible core hardware modules HUNGAROCOM provides FoD (Function on Demand) service. That means, in case of customer’s special function or feature requirements HUNGAROCOM can develop the unique features within short time.

PcmMon key features

The PcmMon equipment is developed for intelligent monitoring of E1 lines. Based on HUNGAROCOM’s CYPCOM-201 core hardware, the equipment has four E1 inputs (PCM Rx). To monitor one E1 line requires two E1 Rx channels, so the hardware can monitor two full duplex E1 PCM lines. E1 Rx lines connect to the E1 lines with high impedance without disturbing the original traffic. The received E1 signal is analysed and processed by the CYPCOM-201’s internal CPU in real time (HDLC frames, DSS1, QSIG, SS7 signalling, Voice channels, DTMF reception are provided). The processed traffic than stored on the built in 2,5” HDD (or SSD).

If the monitored PCM uses DSS1, QSIG, or SS7 signalling the PcmMon detects the call sessions and records the voice channels with related CDRs (communications recording function).

A complex Windows based client application is available to display the stored information. There is some optional off-line post processing function available in the client application (i.e. FAX decoding).

Online channel monitoring is also supported from the client application.

cypcom201 front
cypcom201 back

Front panel connectors (small enclosure)

Front panel connectors (small enclosure)

Front panel connectors (standard rack enclosure)

Front panel connectors (standard rack enclosure)

Technical parameters

  • Number of full duplex E1 lines monitored simultaneously:2
  • Physical connection:High impedance
  • PCM modes:PCM 30, PCM31, unframed, CRC4 and AMI/HDB3 coding supported
  • Real time handled protocols and signals:HDLC, DSS1, QSIG, SS7, DTMF
  • Voice channel recording:call sessions with attached CDRs (CDRs based on DSS1, QSIG or SS7 and in band DTMF)
  • Recording method:records are encrypted and protected against manipulation. Every records and stored events contain exact time stamp.
  • Internal storage capacity: max. 2x1TB 2,5" HDD (or max 2x500GB SSD).
  • Two alarm contacts for minor and mayor alarms.
  • Operation voltage: 230V with external adapter, 48V (or optionally 12V) without external adapter.
  • Client application features: display recorded data, voice record playback and export to standard WAV file. Convenient search functions.
  • Optional off-line processing feature: FAX communication decoding.
  • Size: Standard 1-unit high rack mounted or small enclosure
  • Package content: CYP-201-PCMMON equipment, power adapter, PCM cables and passive TAPs, software, documentation.
  • Size:standard rack enclosure: 483x185x44 mm; small enclosure: 266x189x29,5 mm
The server based communications recording system is suitable to record communications according to protocols SIP, SIP-T, H.232, H.248, RTP. The system is able to record, store and playback VoIP calls with their communications content and call related data, simultaneously in 480 channels.

Network connections of the system

The next Figure introduces generally the connections of the system. It is connected to the IP network, where the communications shall be recorded. The access to the different levels of the network (access, accumulation, backbone) is assured by a switch with mirroring port, or by a tap device connected in parallel to the different medias of the IP network hierarchy. The communications recording system is able to record different communications event depending on the system setup. Local workstations can be connected to the recorder server as introduced in the next Figure via LAN, WAN, and public internet.

connections of the system
connections of the system

The next Figure shows the connection of the recording server to a general PABX, or call manager system.

connection to general PABX, or call manager system
connection to general PABX, or call manager system

Server configuration

Handling 480 simultaneous channels server with the following parameters shall be provided:
  • Type: HP proliant G8 series with redundant power supply
  • CPU: minimum 2,4GHz quad core intel XEON cpu
  • Memory: 8GB, dual channel DDR3 1333MHz
  • HDD: minimum 2x300GB 2,5” SAS Raid-1 (depending on the volume to be stored)
  • Blu-ray drive: for local archivation
  • Gigabit Ethernet: two ports
  • Other: min. 2xUSB port, US

Playback function (in case of audio)

There are transparent GUI menus in the client application to playback records and configure the system. The next Figure shows the playback window with the following functionalities:

  • playback of records from the server
  • introduction of call related data (e.g. time of call, calling and called numbers)
  • showing the time function of the audio record
  • zoom-in and zoom-out within the time function
  • events within a communication
  • quick navigation possibility
  • application of different filtering parameters
  • export records to external data medias
PTI playback

LI Management Systems

Lawful interception

The 21st century has arrived with global societal challenges and the astonishing development of information technologies. Ensuring the security of the nation and actively serving its vital interests requires the ability to control public telecommunications networks and other selected sources of information. Lawful Interception (LI) is the legally approved interception of telecommunications services. It has become an important tool for law enforcement and intelligence organizations worldwide to investigate and prosecute crime and terrorism. The task may only be performed by law enforcement agencies (LEAs) approved by the national authorities.
lawful interception
lawful interception

HUNGAROCOM LIMS, in cooperation with the immanent monitoring function (INI) used by the electronic communications service provider, monitors all types of public communication services in real time including telephone (VoIP, VoLTE) and video calls, messages (SMS, MMS), fax, e-mails and other data communication services. It supports monitoring of 2G (GSM, CDMA, GPRS), 3G (UMTS), 4G (LTE) and 5G wireless networks of all networks, as well as PSTN, IMS and Cable based wired networks.


Implementing the lawful interception (LI) function involves close cooperation between network service providers (NWOs), network access providers and service providers (SvPs) (these three functions can often be performed by the same provider) and the Law Enforcement Agencies (LEA).

Hand over interfaces (HI) are a three-port structure where administrative information (HI1), intercept related information (HI2), and communications content (CC) are logically separated.

Main features of HUNGAROCOM's LIMS

  • Hot standby and geo-redundant solutions.
  • It fulfils the following international and local standards:
    • ETSI: ETSI TS 101 671 (voice), ETSI TS 101 331 (általános), ETSI ES 201 158 (általános), ETSI TS 102 232-1 to 102 232-7 (IP, e-mail, VoIP)
    • ETSI: TS 133 126, TS 133 127, TS 133 128, TS 103 120 (fejlesztés alatt)
    • PacketCable: PacketCable v1.5
  • It handles the following PSTN and VoIP protocols:
  • In case of VoLTE the following transcoding are handled:
    G711A, G711u, G.729, NB, WB, SWB, FB, AMR, AMR-WB, EVS.

Application in Internet access networks

Our solution uses the active monitoring procedure. Network nodes as well as Radius servers provide the ability to monitor both credentials and media streams. As shown, the LIG_AAA device provides the warrants for the Radius servers (INI1a) and receives the call related data (INI2). The LIG device is used to receive media streams from the network node and transmit them as HI3 information to the LEA. The activation of the targets to be intercepted is managed by the LIG device based on the HI1 information via the INI1b interface.

Application for 5G networks

The method (under development) used for 5G networks is based on the relevant ETSI recommendations. The 5G-LIMS device shown in the figure is connected to the corresponding elements of the 5G structure as well as to the LEA on the HI interfaces. The solution provides a seamless transition between 5G functionalities and existing systems, as well as the ability to introduce new services.
Application for 5G networks
Application for 5G networks

Application for performing LI transcoding tasks

The simplified version of the LIMS, the LIG (Lawful Interception Gateway), provides the ability to adapt LIMS from any other vendor (HI') to locally defined HI interfaces.

Mobile Recording Gateway

The demand can emerge from individual organizations, institutions, or companies to control the mobile traffic of their employees on an effective way. The control has two different functions:

  • The recording and archiving of the conversations of the assigned mobile telephones for a possible later use.
  • The flexible assignment of the available parties for calls within or outside the mobile network.
This features can exceedingly be used in the areas of the business life where it is important to store the speech content of telephone calls and their call related data to search it back promptly in case of controversial cases.


Building blocks of the system

  • The Central data base server located at the mobile operator’s site which is common for more organizations joining the service to provide a better utilization. The individual organizations are handled fully separately.
  • The Network and storage server connected to the mobile operator’s network to provide temporary storage of speech and its call related data.
  • Archive server located in the organization’s site to store and archive the speech and call related data belonging to the mobile phones of the relevant organization.
  • Workstations at the organization’s site. One workstation serves for assigning the control conditions of the given mobile telephone, the others serve for the real time monitoring and the playback of the recorded conversations. The assignment is not a continuous activity thus this workstation can also be used for monitoring and playback purposes. The number of workstations is dependent on the traffic requirements.

The principle of operation

The telephone number of the relevant mobile phone and the telephone numbers of its possible partners are fixed from the assigning workstation. These data are stored on the central data base server. The system assures that from the assigned mobile telephone no other numbers can be called.

About the fact of recording the conversation the talking parties receive warning voice announcement (switchable function).

When a call is initiated or received on the mobile telephone assigned, a signal arrives for the operator of the relevant organization. The operator can decide whether he wants to monitor the call in real time or it is for a later playback after recording. All conversations and their call related data (date of the call, called number holding time etc.) are stored on the Mobile network and storage server or on the Archive server located in the organization’s site.

The system assures that only the authorized operators of the relevant organization can have access to its own employee’s records and data.

It is possible to archive certain conversations for an optional media from the Archive server of the organization. Archiving can happen from time to time as well.

The speech records are encrypted (with organization specific master key) and electronically signed which assures that the records belonging to a given organization can be played back by the authorized operators of the same organization only. The playback is only possible by a dedicated software and appropriate authorization.

Different statistics can be prepared for the organizations about the calls and their call relations.


For application of the system compliance is necessary with the mobile operator. The regulations and law regarding personal data handling must also be considered!

Tetra apps

Communications recording is an essential function when operating TETRA system. It helps assisting the dispatcher personals and supervisors in their work, furthermore thanks to the archiving function, it can be used to document important events and communication contents together with their communication related information relevant for a given individual or group call for a later use.

For small TETRA networks where Claricor/Taira DXT(s) is(are) deployed, it is required to provide a compact communication recording solution, which integrates TCS server, storage and client functionality on a single server machine. This product line shall provide all functionalities as defined in this paper below and flexibility and scalability to be applicable for different customer’s need if any. The next Figure introduces the location of the communications recording application in the TETRA system.

Tetra AR-C
Tetra AR-C

Communications (archive) recording means recording of all call related data information together with the speech or data communication. The traffic cases included in the communications recordings are the following:

  • group calls
  • all type of individual calls of radio terminals (incoming, outgoing, simplex, duplex, normal, emergency etc.)
  • all type of individual calls of dispatcher workstations
  • SDS and status messages sent to a group
  • SDS status messages sent to and sent from an individual radio and DWS

For the mentioned traffic cases, the following call related data are recorded:

  • the exact time of the communication and events, call beginning, end, duration
  • calling party SSI, called party SSI; Call ID
  • type of the call (incoming, outgoing, simplex, duplex, normal, emergency…etc), priority
  • TETRA specific: TxGranted, TxCeased events
  • participant list of a group call session
  • other events (i.e. radio terminal tracking information) which are provided on Airbus’s TETRA TCS API

The AR-C communication recorder is available in several versions according to the current capacity, configuration and reliability requirements.
The simplest non redundant version is introduced in the Figure. AR-C server integrates two virtual machines the Recording server and the TCS server.

Recording server and TCS server
Recording server and TCS server

The following figure shows the variant (AR-C full redundant system handling two DXTs) in which AR-C communications recording servers are installed next to two DXT/TAIRAs in a complete redundant arrangement, with which geo-redundancy can be ensured if necessary.

Configurable operating modes:

  • active-standby, when one server handles all traffic and only switches to another in case of an error

  • load sharing, where in load sharing, one server handles DXT1 traffic and the other handles DXT2 traffic

  • full parallel when both servers handle both DXT traffic.

This device is the communications recorder of TMR 880 and TMR 880i dispatcher workstations for fix and vehicle mounted applications.

The main characteristics of the device are the following:

  • recording of voice communications
  • start/stop of the recording by means of line signals, or VOX detector
  • recording of SDS and Status messages
  • simultaneous recording and playback is possible
  • the communication information is stored on an encrypted way
  • voice and call related data are stored in the same file with an inseparable way
  • the recorded data is guarded against manipulation and sabotage by „electronic signature”
  • filtering of information according to the customer’s need
  • export possibility of the recorded information in standard WAV file
  • remote access via LAN or WAN
  • remote operation and management of the devices
  • connection possibility to centralised data base servers and centralised storage
  • connection possibility of external VGA monitor
  • size: length: 300 mm/ width: 165 mm, height: 50 mm
  • power supply: 12V DC/220VAC with 12 V power supply unit

We are proud that the centralized, geo-redundant communications recording (Archive Recording) of the entire Hungarian TETRA system (EDR) is performed by HUNGAROCOM solutions and equipment.

The AR system is designed to centrally record group communications (call events, voice, SDS and status messages) and individual communications (call event, voice, SDS and status messages) furthermore flexibly retrieve/export and archive recorded communications.

The recording function is based entirely on the support of the current latest REL.8 version of the TETRA system. The basic principles are as follows:

  • Audio is recorded with dynamic channel reservation, so much less recording time slots (i.e. E1 channels) are required than SSI communications to be recorded.
  • The control of recording is handled by the call event monitoring function.
  • Audio access is only required for DXTs where the AR system is installed.
  • The principle of user access is that the user/password assigned in the TETRA system can be used, and the system is based on the rights assigned in the TETRA system for each function (communication right, management right, user SSI range…, etc.).
  • User access is provided by a “thick” client software that can run on the DWS machine or on any independent terminal (i.e., for users who does not have a dedicated DWS station but has assigned TETRA user access).

In the case of a redundant system, in normal operation, the two systems operate in load sharing. The two systems keep each other informed of their operating conditions and in the event of a fault, the other system starts recording all calls. If the communication channel that transmits the “life signals” between the two systems is interrupted, in this case both systems record in parallel until the connection improves (temporary redundancy is better than information loss). The figure shows a large AR system with multiple DXTs and geo-redundancy.
AR system with multiple DXTs and geo-redundancy
AR system with multiple DXTs and geo-redundancy
CMS-T together with the mediation device serves for TETRA system level lawful interception both for voice and data communications.

CMS-T is an universal robust system for nationwide networks applications however a simplified versatile economic version was also developed which fits better to the requirements of smaller target networks. This is a special application for the very complex function of the TETRA system.
CMS is able to intercept all kind of features provided by the TETRA system:
  • individual calls
  • group calls
  • SDS, Status messages
  • packet data
  • tracking data
  • subscriber related events

CMS-T is composed from two basic part: the mediation device connected to the central point of the TETRA system, and the information storage and managing centralized system located in the remote end. The main characteristics of the operation:
  • Storage of intercepted information for the authorized time.
  • Composition of target structure.
  • Playback of communication content with the relevant call related information (CRI).
  • Real-time surveillance. The real-time playback is a no wait process.
  • Report writing. The function is supported by an integrated word processor software.
  • Copies of intercepted information. Upon request designated sessions of the recorded information are copied on different storage media for offline use. Such media include CD, DVD. etc.
  • Long-term archive. Sessions or the full contents of communication of designated information sources are stored in the long-term archive for later use and for authentic evidence purposes.
mediation device
mediation device