2.2. Device Control

To simplify IP Media management by the host application and to provide a consistent look and feel with other Global Call technology call control libraries, the IP Signaling call control library (IPT CCLib) controls the IP Media functionality.

When using Global Call with IP technology, two types of devices are used:

• IP Network Device - Used for call control (call setup and tear down). The format of the device name is iptBxTy, where Bx is the logical board number and Ty is the logical channel number.
• IP Media Device - Used to control RTP streaming, monitoring Quality of Service (QoS) and sending and receiving DTMF digits. The format of the device name is ipmBxCy, where Bx is the logical board number and Cy is the logical channel number.

When using Global Call with a DM3 board that uses an embedded call control stack, each IP Media device (ipmBxCy) is bound to a corresponding IP network device (iptBxTy). The IP network device has control over the IP Media device using the device handle.

The IP network device (iptBxTy) and the IP Media device (ipmBxCy) should be opened simultaneously, that is, in the same gc_OpenEx( ) command. See Section 3.1.15, "gc_OpenEx( )" for more information.

The IP Media device handle, which is required for managing Quality of Service (QoS) alarms for example, can be retrieved using the gc_GetResourceH( ) function. See Section 4.7, "Setting and Retrieving Quality of Service (QoS) Thresholds" for more information.

Note: If the IP network device (iptBxTy) and the IP Media device (ipmBxCy) are opened separately, Quality of Service (QoS) functions will fail.

Figure 5 shows the relationship between the various types of Global Call devices used in an IP environment.

Figure 5. Global Call Devices in an IP Environment

Note: The board and channel/timeslot numbers in the ipt (ipt_BxCx) and ipm (ipm_BxTy) devices must be the same, that is, BxCx = BxTy.

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