MS_CDT

---

typedef struct {
      int chan_num;      /* channel/time slot number */
      int chan_sel;      /* meaning of channel/time slot number */
      int chan_attr;     /* channel attribute description */
} MS_CDT;  

Description

The conference descriptor table is an array of MS_CDT structures.

An extended connection can also be described by the descriptor table. For an extended connection, there are two entries in the table. The order of the entries in the table is significant. The first entry must be the connection identifier, the second must be the connection extender.

Field Descriptions

The fields of the MS_CDT data structure are described as follows:

chan_num

denotes the station number or TDM bus time slot number of the device to be included in the conference.

chan_sel

defines the meaning of chan_num. Valid choices are as follows:

• MSPN_STATION

  MSI station number

• MSPN_TS

  TDM bus time slot number

chan_attr

bitmask describing the party's properties within the conference. Valid choices are:

• MSPA_NULL

  No special attributes for party (default)

• MSPA_RO

  Party participates in conference in receive-only mode

• MSPA_TARIFF

  Party receives periodic tone for duration of call

• MSPA_COACH

  Party is a coach. Coach heard by pupil only

• MSPA_PUPIL

  Party is a pupil. Pupil hears everyone including coach

• MSPA_NOAGC

  Disables automatic gain control (AGC)

  Note: If the first party (connection identifier) is in a pupil-coach situation, the party must be defined with the MSPA_PUPIL attribute when the extended connection is established. There is no way of changing the attribute of the first party once an extended connection has been established.

Table 8 shows the allowable combinations of attributes within a conference, where each row represents an allowable combination.

Table 8. Valid Attribute Combinations

Row No.	AGC Disabled	Pupil	Coach	Periodic Tone	Receive-only mode
1					X
2				X
3				X	X
4			X
5		X
6		X		X
7	X	X
8	X	X		X

Notes:

1. Only one coach and one pupil are allowed in a conference at any time.
2. The default MSPA_NULL must be used if channel attributes are not set.
3. The MSPA_NOAGC option should only be used when the connection identifier is a pupil. This ensures that the client will not hear a change in the pupil's volume when the connection is extended.
4. If the coach speaks before any conversation has taken place between the client and the pupil, the client will hear some background noise for a fraction of a second. Under most circumstances, this will not be an issue since the coach generally does not need to speak before some conversation has taken place between the client and the pupil.

Click here to contact Telecom Support Resources