With legislation and an increased desire for companies to improve customer services, it has become important and in some cases mandatory for telephone calls to be monitored, intercepted and recorded. To meet this need Aculab offers a number of variants of the Passive monitor card in PCI and cPCI format, which provide comprehensive call monitoring, conferencing and recording capabilities. The products enable passive monitoring and processing of voice calls in up to four E1/T1 trunks in a single slot.
Architecture
Typically, the Passive monitor operates between the central office/PSTN and the customer premise equipment (CPE) or enterprise PBX. A card's high impedance receivers are connected to both receive and transmit pairs of the E1 or T1 trunk by means of an adapter. This enables monitoring of digital data streams in both directions, feeding call related information back to the application via the device driver API. The passive card simply ‘listens in' to the signalling and all calls in the trunk, without interacting with the signalling and connecting or routing calls.
The passive tap method of connection ensures that the operation of the E1 or T1 trunk is unaffected even if the Passive monitor's function is suspended. This is especially important when considering a contact centre that performs monetary transactions, as any interruption of calls in the trunk could result in a loss of revenue.
Configuration options
Four variants are based on E1/T1 digital network access cards and are suitable for monitoring line activity, routing audio data streams to the H.100/H.110 CT bus for processing by call-logging or recording products. An optional DSP facility can be used to conference both sides of a conversation, prior to routing over the CT bus, so it may be monitored as a single data stream or recorded to disk as a single file for later analysis and archiving.
Four further variants are based upon Prosody media processing resource cards. These support monitoring and in addition, provide media processing resources for conferencing the channels together and recording the conversation directly to file. Developers can take advantage of the range of algorithms available for recording at various data rates, thus optimising disk space needed to store recordings. The Prosody-based Passive monitor card forms the most comprehensive, compact and cost effective solution available.
Call information
Whenever a call is active, the associated D-channel information, for example, CLI/ANI, DDI, or the dialled, originating or connected number, is provided via the monitor API. This allows an application to filter the signalling data and link the call control details with the (B-channel) conversations on the trunk. Calls can then be selected for recording based on specific criteria. In this way, monitoring the use of certain numbers, recording is more economic and there is no need for continual recording irrespective of call activity.
Applications
The cards are particularly useful to developers whose customers specify the need to monitor and record calls going through their digital network, but who don't wish to adapt their current PBX or ACD system. Because the card's architecture ensures that no interference occurs with existing equipment, it is ideal for these situations. Essentially, the Passive monitor is suited to many sophisticated applications required by the call recording industry. See the target applications list for examples.
Time to market advantage
The information presented about the calls is available via an extension to Aculab's consistent API, ensuring fast development and deployment of monitoring and recording solutions. A range of ISDN protocols may be monitored, for example: Q.SIG, ETS300, NI2, AT&T and INS 1500, giving developers the potential to create solutions for worldwide deployment. In addition, where more than one trunk is being monitored, a different protocol can be run on each trunk. To view the list of protocols supported see the protocols and approvals page. The standard set of device drivers includes Linux, SPARC Solaris and Windows XP/2000/Server 2003. To check availability, see software downloads.
Passive monitor architecture
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