Trunk-side and Extension-side Voice Logging

A business telephone system (PBX or Private Branch Exchange) connects a number of network lines (e.g. Telkom lines, Neotel lines, GSM routers, VOIP Lines) to a generally larger number of users (extensions). In order for telephone calls to be recorded, a physical connection is required either from the network lines to the voice logging system, or from each extension telephone which is to be recorded, to the voice logging system.

The cost of a voice logging system is proportional to the number of channels being recorded, so when it is required to record all telephone calls in an organisation, it is generally more cost effective to record the network lines which connect the PBX to the outside world, as there would usually be a lesser number of these lines than user extensions. This is referred to as Trunk-side voice logging and is by far the most common implementation.

In cases where a large enterprise has numerous outside lines, and only a small number of extension users require recording, it is more cost effective to only record the telephone instruments of these specific extension users, and this is referred to as Extension-side voice logging.

Extension-side voice logging is also used where there is a requirement to record internal conversations between extension users, e.g. dealing rooms, treasury departments, hotel administration extensions.

A market tendency towards Trunk-side voice logging

Even where only a small number of extensions need to be recorded within an organisation, there is a growing trend towards trunk-side voice logging, which records all calls between a business and the outside world. This ensures that all users, including management, finance and admin staff are able to retrieve and play back their own calls, and with a Truelog system, users can retrieve their own calls with the same ease as retrieving an email. This can provide significant productivity benefits, which will often outweigh the cost difference between extension-side voice logging of a few extensions, and trunk-side voice logging of all network lines. Where there is concern about the recording of sensitive communications, the Truelog system will be configured to automatically delete any calls involving specifically defined extensions and telephone numbers.

Trunk-side Voice Logging

Recording of calls takes place directly on the incoming lines (Telkom / Neotel / GSM / VOIP lines). All incoming and outgoing calls between the business and the outside world are recorded. Whilst a call is being recorded on the trunk-side, the Truelog system is not aware of which extension is involved with the call, as the extension is on the 'other side' of the PBX. However, all PBX systems provide a SMDR / CDR information data record at the end of each call, and it is common for the Truelog system to be integrated to the PBX using this communication method. This SMDR / CDR info is used to update an external Call Management or Reporting system, and is intercepted by the Truelog system to identify the extensions which are involved with each call, including the splitting of a call into multiple constituent calls where call transfers are involved.

In the case where a CTI (Computer Telephony Integration) connection is available from the PBX, the recording system is updated on a real-time basis, which allows full observation and monitoring of live audio on all trunk lines and extensions. This is usually a primary requirement for voice logging within call centres. Internal calls between extensions are not recorded, as these calls do not make use of an outside line. The system may be set up to automatically delete calls for certain defined extensions (e.g. specific users, guest extensions).

Extension-side Voice Logging

Recording of calls takes place on the Analogue, Digital or IP extension port connections of the recorded telephones. Only those extensions which are connected to the voice logger system are recorded. The Truelog system does not require that any equipment be installed at the telephone instruments or Digital / IP terminals. This eliminates any possibility of tampering with equipment by those extension users being recorded.

All calls at the monitored extensions are recorded, including internal calls (i.e. extension to extension calls). Where a call is transferred between extensions, only that portion of the call which takes place at a monitored extension can be recorded, i.e. when a call is transferred from a monitored extension to another extension which is not being monitored, recording will not continue at the unmonitored extension.

Note: It may also be possible to combine both Trunk-side and Extension-side voice logging of the PBX system, i.e. in addition to the external lines being recorded on the trunk side, any number of extensions requiring internal call recording may also be recorded on the extension side (this would depend on the recording compatibility of the specific telephones).

Call Centre Considerations

In a call centre environment, the trunk-side / extension-side decision needs to take the ratio of inbound to outbound calls into account. If the call centre only makes outbound calls, the recording point becomes irrelevant and the decision is reduced purely to one of channel count.

However, in an inbound environment the argument for trunk-side voice logging is a compelling one, as the following benefits then become available:

Monitoring of Call Ringing Times and Abandoned Calls

Any inbound call centre needs to keep a close watch on these important metrics, as they are primary indicators of call centre efficiency and adequacy of staffing. In the case where all inbound calls are immediately answered by an upfront auto attendant or IVR (Interactive Voice Response) system, it is important to monitor the time spent in inbound queues, as well as the number of calls which are abandoned whilst in queue.

Where CLI (Caller Line Identification) is activated on the trunk lines, all abandoned calls are logged with the calling party's number, allowing prospective customers to be called back.

Recording of calls transferred to or from non-call-centre extensions

When an agent transfers a call to admin, accounts, back office etc, the call will continue to be recorded. Conversely, trunk side recording ensures that calls transferred to the call centre from other extensions are recorded from beginning to end.

Filtering of calls based on DDI number dialed

Where multiple product lines are handled in a call centre, calls can be selected and quantified on the basis of the DDI (Direct Dial Inward) numbers on which the calls enter the queues, irrespective of the agents or groups which handle the calls.

Traffic Analysis

Traffic Charts can be plotted to indicate the number of simultaneous calls on specific trunk groups over a selected period of time, and can be filtered by specific destinations (e.g. dialling codes) and specific agent or extension groups. This provides important information for call centre optimization, varying from the 'dimensioning' of lines and trunk groups, to staff utilization across different agent groups. Traffic charts are also useful at revealing trends and campaign performance / results.

In conclusion, extension-side voice logging captures an agent's interaction with the customer, whereas trunk-side voice logging captures the customer's interaction with the business as a whole, including IVR navigation, time spent in queues etc.

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