SRST routers support also the call transfer between IP Phones by default when they are registered onto it. But to really have a successful transfer call , you need also to precise the pattern transfer and the way on how it will transfer your call. So don’t forget to implement these commands:

!
call-manager-fallback
transfer-pattern <<pattern>>
transfer-system <<method>>
!

What are representing the parameters ?

  • <<pattern>> is the pattern that you authorize to dial under SRST mode ( example …. or .T)
  • <<methods>> is the call transfer method operation.

Let’s see what are the operation mode possible:

  • Blind : Cisco proprietary method where calls are directly transferred without any consultation.
  • Full-blind : H450v2 standard for call transfer where calls are directly transferred without any consultation.
  • Full-consult : H450v2 standard for call transfer where you need to perform a consultation before to initiate the real transfer. This method requires two line to make the transfer and if the second line is not available then the full-blind is used instead.
  • Local-consult : H450v2 standard for call tranfert but this time, it is only valid for local transfers.So again if you don’t have the second line or you are not transferring to a local party , the blind method is used instead.

Full-blind and full-consult are the Cisco preferred method.

Don’t forget also to configure your line as dual-line to allow not only the call transfer but also the call waiting , conferencing and so on