4.1. ISDN Library Function Categories

The ISDN library functions can be divided into the following categories:

• Call Control - Perform basic call control actions, such as making, receiving, answering and dropping calls (see Table 9).
• Optional Call Handling - Perform additional call control actions, such as accepting calls, sending messages to the network, and setting and retrieving call-related information (see Table 10).
• System Control - Start and stop the system, that is, open and close devices and reset channels (see Table 11).
• System Tools - Perform system level tasks (see Table 12). These functions are divided into the following categories:
  • Configuration Tools - set and retrieve channel parameters and user attributes, and retrieve call states, call reference numbers, call reference values, etc.
  • Error Handling - retrieve error information (cause values and result values)
  • Tracing Functions - capture and store D channel information
  • Eventing Functions - set and retrieve event masks
• Data Link Layer Handling - Send and receive frames, that is, handle the transfer of frames between the application and the data link layer (see Table 14).
• Hold and Retrieve - Process calls on hold. These functions are used in BRI protocols and in the PRI DPNSS and Q.SIG protocols to place calls on hold, retrieve calls from the Hold state, and to accept and reject hold requests and retrieve-from-hold requests (see Table 14).
• Global Tone Generation - Set, change, and control the In-band tones for BRI/SC protocols (see Table 15).

Table 9. Call Control Functions

Function	Description
cc_AnswerCall( )	accepts a connection request from the remote end
cc_DropCall( )	allows the application to disconnect a call
cc_MakeCall( )	requests connection on the specified line device
cc_ReleaseCall( )	releases the call reference number (CRN)
cc_ReleaseCallEx( )	releases all resources for the specified call (CRN)
cc_WaitCall( )	sets up the condition for processing an incoming call

Table 10. Optional Call Handling Functions

Function	Description
cc_AcceptCall( )	responds to an incoming call request
cc_CallAck( )	sends the first response to an incoming call
cc_CallProgress( )	sends a PROGRESS message to the network
cc_GetANI( )	retrieves Automatic Number Identification (ANI) information (caller ID)
cc_GetBilling( )	retrieves the charge information
cc_GetCallInfo( )	retrieves the information elements associated with the CRN
cc_GetChanId( )	retrieves the last channel information received from messages for a specified CRN
cc_GetDNIS( )	retrieves the dialed number information string (destination address)
cc_GetInfoElem( )	retrieves the information elements associated with a line device
cc_GetMoreDigits( )	collects more digits via overlap receiving
cc_GetNonCallMsg( )	retrieves the information associated with a GLOBAL or NULL CRN event
cc_GetSigInfo( )	retrieves the signaling information of an incoming message
cc_GetVer( )	retrieves the library version number
cc_ReqANI( )	requests the ANI (caller ID) from the network in ANI-on-demand environments
cc_SetBilling( )	sets the billing rate
cc_SetCallingNum( )	sets the default calling number
cc_SetInfoElem( )	sets an information element (IE)
cc_SetMinDigits( )	sets the minimum number of digits to be collected
cc_SndMsg( )	sends a non-call state associated message to the network
cc_SndNonCallMsg( )	sends a non-Call State related ISDN message to the network, with a GLOBAL or NULL CRN

Table 11. System Control Functions

Function	Description
cc_Open( )	opens a device
cc_Close( )	closes a previously opened device
cc_Restart( )	resets the channel to the Null state

Table 12. System Tool Functions

Function	Description
Configuration Tools:
cc_CallState( )	retrieves the state of the call
cc_CRN2LineDev( )	returns the line device number associated with a specified call reference number
cc_GetCES( )	retrieves the connection endpoint suffix
cc_GetCRN( )	retrieves the call reference number
cc_GetDChanState( )	retrieves the status of the D Channel
cc_GetDLinkCfg( )	retrieves the configuration of a logical link
cc_GetDLinkState( )	retrieves the logical data link state
cc_GetNetCRV( )	retrieves the network call reference value for a specified call reference number
cc_GetParm( )	returns the default channel parameters
cc_GetParmEx( )	retrieves parameters containing variable data passed from the firmware.
cc_GetSAPI( )	retrieves the service access point ID
cc_GetUsrAttr( )	returns the user attribute
cc_SetChanState( )	changes the maintenance state of an indicated channel
cc_SetDChanCfg( )	sets the D-channel configuration for a BRI station device
cc_SetDLinkCfg( )	configures a logical link
cc_SetDLinkState( )	sets the logical data link state
cc_SetParm( )	sets default call parameters
cc_SetParmEx( )	sets parameters requiring variable data to be passed down to the firmware
cc_SetUsrAttr( )	sets the user attribute
Error Handling Functions:
cc_CauseValue( )	retrieves the cause of the last failure on a given device
cc_ResultMsg( )	returns a pointer to an error string
cc_ResultValue( )	retrieves the error/cause code related to an event
Tracing Functions:
cc_StartTrace( )	starts the capture of all D channel information into a specified log file
cc_StopTrace( )	stops the trace and closes the file
Eventing Functions:
cc_GetEvtMsk( )	retrieves the current ISDN event mask
cc_SetEvtMsk( )	sets the event mask
cc_TermRegisterResponse( )	sends the acknowledgment for the CCEV_TERM_REGISTER event

Table 13. Data Link Layer Handling Functions

Function	Description
cc_GetFrame( )	retrieves the frame received by the application
cc_SndFrame( )	sends a frame to the data link layer
NOTE: These functions are available only when Layer 2 access is configured.

Table 14. Hold and Retrieve Functions

Function	Description
cc_HoldCall( )	places active calls on hold
cc_HoldAck( )	accepts hold requests from remote equipment
cc_HoldRej( )	rejects hold requests from remote equipment
cc_RetrieveCall( )	retrieves a call placed on hold from Hold state
cc_RetrieveAck( )	accepts a retrieve from hold request from remote equipment
cc_RetrieveRej( )	rejects a retrieve from hold request from remote equipment

Table 15. Global Tone Generation Functions

Function	Description
cc_PlayTone( )	plays a user-defined tone
cc_StopTone( )	stops the tone that is currently playing on a channel
cc_ToneRedefine( )	redefines the tones in the firmware tone template table

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