Telephony

Ring Timeout Management

Correct Ring No Answer (RNA) timeout control is critical to both dialer performance and compliance. There has been some confusion regarding correct setting of the RNA timeout, particularly when calling to GSM networks where network latency can be as much as 10 seconds.

The right way to interpret RNA timeout is 'the time that the call should ring before timing out'. In territories where Q.931 signalling is implemented there is a simple approach that will yield the best results, as follows:

1. At the point of launching a call, set the no answer timer to fire 3 seconds after the configured timeout value; i.e. if the configured RNA timeout is 15 seconds, set the timer for 18 seconds.
2. If and when the network reports PROCEEDING for the first time on that call, i.e. the carrier has accepted the call as valid and established a route through the network, reset the timer to the configured value (15 seconds in the example above).
3. If and when the network reports ALERTING for the first time on that call, i.e. the far end exchange has started to ring the called party, reset the timer to the configured value (15 seconds in the example above).

PROCEEDING and ALERTING messages may not necessarily arrive. In the UK terrestrial network they will be reliable but going into the GSM network this may not be the case, hence the need for a belt-and-braces approach to call timeouts.

Using DisconnectHint

It is often the case that PBX and CT board manufacturers' timeout mechanisms do not work properly or do not have the granularity to time calls out after an exact number of seconds. Since accurate handling of RNA is critical to good dialer performance, integrators who experience problems with RNA settings should consider using the Disconnect Hint [DH] message to tear calls down. Disconnect Hint [DH] is intended to provide a hint for the telephony layer to disconnect a ringing call.

If the Trunks Open [TO] message includes the Disconnect Hint (DH) parameter, the Disconnect Hint [DH] message will be sent for each ringing (and not answered or failed) call at the interval specified by the Ring Timeout (RI) parameter on the Call Initiate [CI] message.

This allows CRM applications which don't talk directly to the telephony layer to control how long numbers ring before hangup occurs, when no one answers. See also Communication Links.

Setting Ring Timeout

Per campaign

A campaign-wide setting is available using the Ring Timeout (RI) parameter of the Overdial Tuning [OT] message. This applies to all calls.

Acceptable values are from 15 - 22 seconds, unless the locale for which Softdial CallGem™ has been installed (set at installation time) requires a higher minimum ring time. This timespan encompasses two variables. The first is any signalling delay before a phone starts ringing; this can sometimes be as much as 3-4 seconds.

The second variable is the allowance for ring time that is heard by a called party. Except under exceptional circumstances, this value should be in the range of 15-18 seconds. Attempts to go beyond these limits will default according to the following table:

RI Value set at...	Defaults to...	Comment
Below 12 secs	Ring Timeout (RI) Error 593	Ring Timeout (RI) parameter value out of range. (For backwards compatibility)
12 - 15 secs	15 secs	Until July 2003, Softdial CallGem™ complied with the UK and US Direct Marketing Association (DMA) guidelines of 12 seconds. These have since been superceded by the US Federal Trade Commission (FTC) ruling of 15 seconds. Therefore, in keeping with our long-term committment to responsible dialing, as of version 8.1 Softdial CallGem™ does not allow values of less than 15 seconds, worldwide.
Less than locale min. ring time (if that is higher than 15 secs)	Ring Timeout (RI) Error 594	Ring Timeout (RI) parameter value is too low to meet regulations.
22 - 60 secs	22 secs	Although there are no published guidelines on maximum ring time, Sytel believes that ring times over 22 seconds do nothing to improve contact ratios and negatively impact Softdial CallGem™ efficiency. For users with sound business reasons for going above this level, please contact your local Sytel representative.
Above 60 secs	Ring Timeout (RI) Error 593	Ring Timeout (RI) parameter value out of range. (For backwards compatibility)
Not specified	16 secs	When this parameter is not used, it is likely that an integration partner will have encapsulated the whole of Softdial CallGem™ in its software, and under these circumstances will probably be handling the ring timeout itself, separately from Softdial CallGem™ API. If this is the case, the default value supplied by Softdial CallGem™ will/ should be ignored.

Per call

Campaign-wide settings, whether made in the Overdial Tuning [OT] message or made by default can be overridden by including the Ring Timeout (RI) parameter in Make Call [MC] messages. This parameter in these messages are also limited according to the table in Setting at campaign level above.

If a campaign includes a lot of retired people, then (on the basis that retired people might be slower to answer the phone) a CRM application might easily do a search on age before passing numbers to be dialed, incrementing the parameter in this message in line with age.

Ring Timeout (RI) parameters specified in Make Call [MC] messages will be passed on to telephony layer by Softdial CallGem™ in Call Initiate [CI] messages.