Linksys ATA Administration Guide
79
Configuring VoIP Failover to PSTN
Configuring the PSTN (FXO) Gateway
Gateways 1 to 4 can be specified in a dial plan with the special identifier gw1, gw2, gw3, or gw4.
Also, gw0 represents the internal PSTN gateway via the FXO port. You can specify in the dial
plan to use gw
x
(
x
= 0,1,2,3,4) when making certain calls. In general, you can specify any
gateway address in the dial plan. In addition, three parameters are added that can be used with
call routing:
•
usr—User-id used for authentication with the given gateway
•
pwd—Password used for authentication with the given gateway
•
nat—Enable or disable NAT mapping when calling the gateway
The following table lists some examples.
You can set up multiple PSTN gateways at different locations and configure Line 1 to use a
different gateway when dialing specific numbers.
Configuring VoIP Failover to PSTN
When power is disconnected from the SPA3102 or AG310 device, the FXS port is connected to
the FXO port. In this case, the telephone attached to the FXS port is electrically connected to
the PSTN service via the FXO port. When power is applied to the Linksys ATA device, the FXS
port is disconnected from the FXO port. However, if the PSTN line is in use when the power is
applied to the Linksys ATA device, the relay is not flipped until the PSTN line is released. This is
done so that the Linksys ATA device does not interrupt any call in progress on the PSTN line.
When Line 1 VoIP service is down (because of registration failure or loss of network link), the
Linksys ATA device can be configured to automatically route all outbound calls to the internal
gateway using the parameter listed below.
Example
Description
<9,:>xx.<:@gw1
Dial 9 to start outside dial tone, followed by one or more digits, and
route the call to Gateway 1.
[93]11<:@gw0>
Route 911 and 311 calls to the local PSTN gateway
<8,:1408>xxxxxxx<:@pstn.Linksys.com:506
1;usr=joe;pwd=joe_pwd;nat>
Dial 8 to start outside dial tone, prepend 1408 followed by seven
digits, and route the call to pstn.Linksys.com:5061, with user-id = joe,
and pwd = bell_pwd, and enable NAT mapping
<8,:1408>xxxxxxx<:@gw2:5061;usr=”Alex
Bell”;pwd=”anything”;nat=no>
Dial 8 to start outside dial tone, prepend 1408 followed by seven
digits, and route the call to Gateway 2, but use the given port, user-id,
and password, and no pstn.Linksys.com:5061, and with user-id =
“Alex Bell” and pwd = bell_pwd, and disable NAT mapping
Parameter
Web
Page
Description
Value
Auto PSTN Fallback
Line 1
If enabled, the Linksys ATA device automatically routes
outbound calls to Gateway 0 when registration fails or
network link is down.
The default is
yes
.