System information

Advanced Options for Voice Services

VoIP-to-PSTN and PSTN-to-VoIP Calling

Cisco SPA232D Administration Guide 208

Sharing One VoIP Account Between the PHONE and LINE

Ports

Both the PHONE port (Line 1) and LINE port (PSTN) can receive incoming calls for a

single VoIP account. Consider the following points:

• If the service provider allows multiple registration contacts and

simultaneous ringing, both lines can register periodically with the service

provider. In this case, both lines receive inbound calls to this VoIP account.

The PSTN Line should be configured with a sufficiently long answer delay

before the call is automatically answered to allow for the function of the

PSTN gateway.

• If the service provider does not allow more than one register contact, the

PSTN Line should not register. In this case, only Line 1 rings on the inbound

call to this VoIP account because it is the only line registered with the

service provider.

• Line 1 can have the call forwarded to the PSTN Line after a few seconds

using the Call-Forward-On-No-Answer feature with gw0 as the forward

destination. Similarly, Line 1 can apply Call-Forward-All, Call-Forward-On-

Busy, and Call-Forward-Selective feature, and direct the caller to the PSTN-

Gateway.

• Only PIN authentication is allowed when a VoIP caller is forwarded to the

PSTN-gateway from Line 1. If HTTP Authentication is used, the caller is not

authenticated.

• When using the Forward-To-GW0 feature, you can forward the caller to a

specific PSTN number, using the syntax <

PSTN-number

>@gw0 in the

forward destination. When using this with Call-Forward-Selective, you can

develop some interesting applications. For example, you can forward all

callers with 408 area code to 14081234567, or all callers with 800 area

code to 18005558355 (This is the number for Tell Me). When this syntax is

used, authentication is not used and the target PSTN number is

automatically dialed by the ATA device after the caller is forwarded to gw0.