Cisco SPA1001 Administration Guide - Page 76

How PSTN-To-VoIP Calls Work Chapter 4 Configuring the PSTN Gateway (FXO) Table 1-28 Two-Stage Dialing Parameter VoIP Caller 1/2/3/4/5/6/7/8 PIN VoIP Caller 1/2/3/4/5/6/7/8 DP Group PSTN Line Description Values The PIN for VoIP Caller 1, 2, 3, 4, 5, 6, 7, or 8. 31-character string PSTN Line Specifies which dial plan to be used for this VoIP caller. If 0, dial plan processing is disabled; the given target number is dialed to the PSTN as is. Choice of 1 to 8 How PSTN-To-VoIP Calls Work PSTN-To-VoIP calls can be made with two-stage dialing only. The only authentication method available is the PIN method. The SPA3102 takes the FXO port off hook after a configurable number of rings. If PIN Authentication is enabled, it prompts the caller to enter the PIN number followed by a # key. The Inter-PIN-digit timeout is set at 10 seconds. Up to eight PSTN PIN numbers can be configured in the SPA3102. If the given PIN does not match any of the PSTN PIN values, the SPA3102 plays the reorder tone to the FXO port for up to 10 seconds, and then takes the FXO port on-hook. If the given PIN matches one of PSTN PIN values, the SPA3102 plays dial tone to the FXO port and is ready to accept digits for the target VoIP number from the PSTN caller. The collected digits are processed by the dial plan associated with the PIN number. Note If Authentication is disabled, a default dial plan is used for all PSTN callers. Terminating Gateway Calls There are two call legs in a PSTN gateway call: the PSTN call leg and the VoIP call leg. A gateway call is terminated when either call leg is ended. The SPA3102 takes the FXO port on-hook when the call terminates so the PSTN line can be used again. The SPA3102 detects that the PSTN call leg is ended when one of the following conditions occurs during a call: • The PSTN Line voltage drops to a very low value (this occurs if the line is disconnected from the PSTN service or if the PSTN switch provides a CPC signal) • A polarity reversal or disconnect tone is detected at the FXO port • When there is no voice activity for a configurable period of time in either direction at the FXO port When any of the above occurs, the SPA3102 takes the FXO port on hook and sends a BYE request to end the VoIP call leg. On the other hand, when the SPA3102 receives a SIP BYE from the VoIP during a call, it takes the FXO port on hook to end the PSTN call leg. In addition, the SPA3102 can also send a refresh signal periodically to the VoIP call leg to determine whether the call leg is still up. If a refresh operation fails, the SPA3102 ends both call legs. Table 1-29 lists parameters for terminating gateway call parameters. Linksys ATA Administrator Guide 4-4 Document Version 3.1