Specifications

4 Message Reference
80
4.3.6 MVD_MSG_SC_LISTEN - CT Bus Listen Request
Synopsis
Message sent to the board to establish a connection from the CT Bus to an outgoing
timeslot on a T1/E1/J1 Line Interface Unit (LIU).
Format
MESSAGE HEADER
Field Name
Meaning
type
MVD_MSG_SC_LISTEN (0x7e17)
id
0
src
Sending module's Id
dst
MVD_TASK_ID
rsp_req
Used to request a confirmation
hclass
0
status
0
err_info
0
len
6
PARAMETER AREA
Offset
Size
Name
0
2
liu_id
2
2
timeslot
4
4
sc_channel
Description
This message is sent to the board to establish a connection from the CT Bus to an
outgoing timeslot on the T1/E1/J1 LIU. It is issued by the application and is typically
used at the start of each call, although it may also be issued during a call to connect to
a different resource.
Correct operation of this message is dependent upon the use, at initialization time, of
the MVD_MSG_SC_DRIVE_LIU message (or the LIU_SC_DRIVE command in the
config.txt protocol configuration file when using the s7_mgt protocol configuration
utility).
When a new call arrives, the application should use this message to connect the
appropriate resource from the CT Bus out to the network. When the call finishes the
application should use the MVD_MSG_SC_FIXDATA message to generate the
appropriate Idle pattern on the LIU. Refer to Section 3.4, “Using the CT Bus” on page
34 for more information.
The MVD_MSG_SC_LISTEN message can also be generated at configuration time using
the s7_mgt protocol configuration utility as a result of the SCBUS_LISTEN command in
the config.txt protocol configuration file. However, this only sets up a static
configuration and still requires the user application to control any dynamic connections.
Parameters
The MVD_MSG_SC_LISTEN message includes the following parameters: