If the phones are conencted to a gateway having TCL IVR capability and the users are required to dial the called-number number after going off-hook, this is how it can be done:
Modify the session TCL application (app_session.tcl)
so that the intial digit timeout for digit collection is 1-x minultes in proc act_Setup. You have to set the required value in param(initialDigitTimeout) before calling "leg collectdigits leg_incoming param". Now, check for digit collect timeout (cd_001) in proc act_GotDest. If the digit collect status is cd_001, place a call to the required emergency number like this:
elseif { $status == "cd_001" } {
puts "Digit collect timed out"
puts "Placing call to $emergency_no"
leg setup $emergency_no callInfo leg_incoming
}
Load the TCL application in the gateway and configure it under the required POTS dial-peers.
Please refer TCL IVR programming guide for more info:
http://www.cisco.com/en/US/products/sw/voicesw/ps2192/products_programming_reference_guide_chapter09186a00800de1ec.html
Muthu