Version 6.2 235 February 2011
SIP User's Manual 8. IP Telephony Capabilities
8.2.4.2.1 FXO Operations for IP-to-Tel Calls
The FXO device provides the following operating modes for IP-to-Tel calls:
One-stage dialing (see ''One-Stage Dialing'' on page 235)
• Waiting for di
al tone (see ''Two-Stage Dialing'' on page 236)
• Time to wait before di
aling
• Answer supervision
Two-stage dialing (see ''Two-Stage Dialing'' on page 236)
Dialing time:
DID wink (see ''DID Wink'' on page 237)
8.2.4.2.1.1 One-Stage Dialing
One-stage dialing is when the FXO device receives an IP-to-Tel call, off-hooks the PBX
line connected to the telephone, and then immediately dials the destination telephone
number. In other words, the IP caller doesn't dial the PSTN number upon hearing a dial
tone.
Figure 8-2: Call Flow for One-Stage Dialing
One-stage dialing incorporates the following FXO functionality:
Waiting for Dial Tone: Enables the device to dial the digits to the Tel side only after
detecting a dial tone from the PBX line. The ini file parameter IsWaitForDialTone is
used to configure this operation.
Time to Wait Before Dialing: Defines the time (in msec) between seizing the FXO
line and starting to dial the digits. The ini file parameter WaitForDialTime is used to
configure this operation.