The gateway can be configured to notify the outbound side for an inbound call:

It is also possible to delay the outbound side notification action by few milliseconds after the gateway met the specified condition.

NOTES:

  1. The "outbound side" is usually a SIP leg. But it can't be another PSTN leg. The type of the outbound leg depends on routing-rules.
  2. The caller-ID information is not available when the gateway is configured to notify the outbound side just after the first ring.