Failover switches (also called Fallback, Line Protection, or A/B Fallback switches) can switch a circuit between two based on a manual or automatic trigger. Some can be controlled via TCP/IP.

• POTS line failover
  • Use a line splitter and hope Asterisk does not fail off-hook
  • Use a line splitter that gives priority to one line (the backup line) See http://www.willyselectronics.com/pdfs/telephone.pdf and search for PN 30-9330 "Message Stopper".
  • Viking Electronics makes a failover device for up to 6 lines: PF-6
  • DataProbe switches (some controllable via TCP/IP)
  • Cornet Technology switches
  • WTI switches (some controllable via TCP/IP)
  • the Sipura SPA 3000 has one fxo and one fxs port. If the power goes out it will automatically connect the two ports
  • Shang332 provides power down and ip down failover. it can failover to pstn and also to another ip peer.
  • berofos Failover Switch for Asterisk (controllable via Webbrowser)
  • FailSafeVOIP Automatically Switch T1/E1/BRI/POTS Connections on failure
  • Rhino Single Port Failover Switch USB controlled

• T1 failover
  • DataProbe switches (automatic failover and TCP/IP Control
  • Cornet Technology switches
  • WTI switches (some controllable via TCP/IP)
  • berofos Failover Switch for Asterisk (controllable via Webbrowser)
  • FailSafeVOIP Automatically Switch T1/E1/BRI/POTS Connections on failure
  • Rhino Single Port Failover Switch USB controlled

• RS-232/V.35/etc failover
  • Hullspeed switches (some controllable via TCP/IP)
  • Altecon switches
  • DataProbe switches (some controllable via TCP/IP)
  • Cornet Technology switches
  • WTI switches (some controllable via TCP/IP)

• Ethernet failover
  • WTI switches (some controllable via TCP/IP)
  • DataProbe switches (some controllable via TCP/IP)
  • FailSafeVOIP Automatically Switch T1/E1/BRI/POTS Connections on failure
  • Rhino Single Port Failover Switch USB controlled

• generic RJ-45 failover (POTS,PRI,BRI,Ethernet...)
  • ISDNGuard from Junghanns, keep-alive via RS-232
  • Rhino Single Port Failover Switch USB controlled

• ISP failover
  • Having multiple connections to the Internet from different providers can be a challenging configuration puzzle. Some routers are designed to make this easy for simple installations.
  • See the Small Routers with Multiple WAN Interfaces section in VOIP Routers for more information.

The following is not really a failover type of product, but it might be useful for some people:

• T1/E1 Multiport Repeaters
  • GL Communications Single/Dual Multiport Repeaters.

Description: The single version provides ten identical outputs from a single T1/E1 input. The dual version provides four outputs for each of two inputs. So you could use this to connect one or two T1/E1 to multiple Asterisk servers (where one server would of course not be running Asterisk until the other server is dead)