Make a Call

Making a Call may take time. A 202 status code is returned if the Call request was successfully queued by FreeClimb. Otherwise, a 500 error is returned. The asynchronous callback for the result will occur after some time through the callConnectUrl.


International Calling is disabled by default.

A synchronous callback for the result will occur after some time through the callConnectUrl of the associated application.

Further details about specific parameters can be found below:

applicationId v. callConnectUrl
callConnectUrl provided via application?callConnectUrl provided via HTTP request?FreeClimb uses
✅ Yes❌ NocallConnectUrl via application
✅ Yes✅ YescallConnectUrl via HTTP request
❌ No✅ YescallConnectUrl via HTTP request
❌ No❌ NoError
sendDigits examples

The pause duration is equal to n × 0.5 s (the default pause interval). As a result, {2} equals a 1-second pause, {3} equals a 1.5-second pause, and so on.

A digits string such as 12{2}34{4}# is rendered as follows:

  • Play digit 1; wait 0.5 seconds
  • Play digit 2; wait 1 second
  • Play digit 3; wait 0.5 seconds
  • Play digit 4; wait 2 seconds
  • Play digit #
ifMachine attributes

This attribute can be set to one of the following values:

  • redirect to invoke the ifMachineUrl for instructions.
  • hangup to hang up the Call. The ifMachineUrl will not be invoked.

if the ifMachine attribute is empty, processing of the Call continues normally.


ifMachine uses the tone stream to detect an answering machine. Therefore, it is not perfectly accurate and may not work reliably in all countries.
callConnectUrl almost always is invoked before the ifMachineUrl. Therefore, if PerCL returned by callConnectUrl is being executed when a machine is detected, the execution is affected as follows if this flag is set to redirect or hangup:

  • If set to hangup, the Call is hung up.
  • If set to redirect, the currently executing Call connect PerCL is aborted, and ifMachineUrl invoked. If the dialed Call has already been placed in a conference, it is up to the application to decide what to do when the ifMachineUrl is invoked.
ifMachineUrl example


A PerCL response is expected to control the Call.

ifMachineUrl is invoked using HTTP POST with the following parameters (in addition to the standard request parameters):

machineTypeansweringMachine or faxMachine.
Click Try It! to start a request and see the response here!