Signalling Issues
This section contains various telephony terms. If you are unsure about anything,
The choice of signalling system used to communicate with the PSTN can either help or hinder the performance of Softdial CallGem™. Typically, the shorter the amount of time taken to classify a call as live, failed (busy, not in service etc) or Ring No Answer, the better a campaign's predictive performance will be. This is true regardless of how the pacing engine works.
This topic deals with signalling issues at a high level. For advice on country-specific signalling systems,
Most countries have adopted the T1 or E1 channelised voice data standard, T1 being 24 channels of 8-bit data sampled 8K times per second, E1 being 32 channels of the same.
Signalling line status and call activity on these channels is achieved through the use of a signalling protocol. Signalling protocols generally take two forms:
- CAS (Channel Associated Signalling) - embeds the signal information in the voice channel.
- CCS (Common Channel Signalling) - uses one of channels as a dedicated signal channel to carry the signalling protocol.
As a rule one should always use a CCS based protocol. CAS protocols are far slower than CCS and less reliable. For reasons of ease of support and reliability we recommend using Q.931 for network-facing trunks. In Europe this is commonly known as Euro-ISDN or ETS300. In the US the two variants are AT&T and NI2.
Basic call classification
The Q.931 protocol provides a complete set of call classification events. As long as telephony layer events are reflected back to Softdial CallGem™ accurately this is all that is needed to ensure good telephony performance.
However, in countries such as the USA not all exchange switching equipment can support this signalling protocol. Where this is the case, there may be inband (CAS) signal information or there may not. The only reliable method of determining the call outcome is to have some means of monitoring the audio signal, as well as handling all other signalling.
Passing call outcome information back to Softdial CallGem™
It is vital that accurate call outcome information is passed back to Softdial CallGem™ as it can have a dramatic effect on call centre performance. The answer drop rate is on average 80% and information on dropped calls needs to be sent to Softdial CallGem™. It is essential to know the call type, i.e. number not in service, so that this number does not get passed back to Softdial CallGem™ and retried at a later date. If an unclassified call gets passed to an agent, they need to be able to identify the call type (i.e. answering machine or number out of service) as quickly as possible.
Fast busies
A fast busy (also commonly known as network busy, network congestion or reorder) is when a network provider does not have the capacity to deal with the volume of calls being produced by Softdial CallGem™ and as a result the call will fail. It is important that 'fast busies' are classified correctly otherwise Softdial CallGem™ will increase the dialing rate as it will assume that a large number of calls are failing. However, increasing the dialing rate will only intensify the problem. (See also Resilience Measures - Network Provider Issues)
False abandons
Any incidence of false abandons not only undermines the performance of Softdial CallGem™, but is likely to push recorded abandoned calls well above the target level set for a campaign. When this happens, integration partners should inspect their logs and check agent status at the time that calls are abandoned. If agents are indeed free and available, then they should check out their telephony code for handling calls in conjunction with Softdial CallGem™.
If integrators are not sure how to address and solve issues of false abandons,