Dialogic 6.2 manual Outgoing Call Processing, November 298

Ground Start Signaling

Outgoing Call Processing

If send_glare_err_event = 0 in the IISDN_ROBBED_BIT_DATA structure, the host receives an L3L4mERROR message containing the value L3L4errGLARE if the outgoing call attempt fails due to glare. Glare occurs when the module attempts to make an outgoing call on a channel at the same time an incoming call arrives on the channel. The call attempt fails because the network always wins channel contention.

During an outgoing call, the host receives an L3L4mPROGRESS in response to the L4L3mCALL_REQUEST to start the call. The module starts the fixed pause timer when it detects tip ground at the far end (FXO end). When the timer expires, the host receives an L3L4mSEIZE_COMP message if send_seize_comp_event = 1 in the IISDN_ROBBED_BIT_DATA structure.

FXS ground start supports transmitting digits other than dial pulse digits. If called_party_digits = 0 in the L4L3mCALL_REQUEST that started the call, the module waits in outdialing state indefinitely.

During that time, another device connected to the Brooktrout module over the TDM bus (such as a digital tone generator) is used to outpulse digits to the network.

After the digits are transmitted, the module waits for an answer timer to expire (if timed_answer_supervision = 1). When the timer expires, the host receives an L3L4mCONNECT indicating the call is connected.

Figure 36 shows how the module makes an outgoing call over an FXS ground start trunk.

Call Teardown Processing

For an incoming call teardown, refer to Figure 37; for an outgoing call teardown, refer to Figure 38.

November 2009 298