The dial tone generated by a PSTN connection or a PBX can be extended over the Internet or an Intranet by using a pair of Smartnode 452x units or a Smartnode 452x and a Smartlink 402x unit. This FAQ describes how to perform dial tone extension using a Smartnode 452x and a Smartlink 402x. Smartnode to Smartnode configuration information is available under "Line Extensions" of the SN452x applications notes page. Once the setup is complete, the end user will be able to lift the handset on the analog phone, hear the dial tone from the PSTN or PBX and then dial a number just as if they were directly connected to the PSTN or PBX. Flash-hook is supported so features like call waiting and call hold will work. Tax pulse tone (not typically used in the USA) is not supported. The guide below assumes that WAN and LAN connectivity has already been established.

Hardware –

• Smartlink 4021 or Smartlink 4022

• Smartnode 4522, 4524, 4526 or 4528 with FXO ports (order code “JO” indicates FXO ports)

• PSTN analog connection OR PBX with analog phone port

• Analog phone

Physical Connectivity
Analog phone ----SL402x----- Internet/Intranet -----SN452x-------PSTN or PBX

In the SL4020

• Under Telephony, SIP –

  • Set “SIP Registration Server Address:” to the IP address or domain name of the SmartNode 4520

  • Uncheck “Send Registration Request with Expire Time:”

  • Save the changes

• Under Telephony, Phone 1

  • Set the phone number to the phone extension (example 111).

  • Optional - You can set caller id if you wish.

  • Under “Dial Out Type” , select Hotline from the drop down menu

  • Under “Hot Line Number”, enter the phone number that has been routed to the FXO port on the SN452x.

  • Save the changes

• Go to System,Reload and restart the SL4020

In the SmartNode 452x....Please use the Smartnode CO configuration information under "Line Extensions" of the SN452x applications notes. You will need to add call routing and mapping table to strip the called number that is passed from the Smartlink.

routing-table called-e164 TAB-IN
route ... dest-interface IF_FXO0 STRIP
mapping-table called-e164 to called-e164 STRIP
map ...% to \1
map default to ''