Controlling the B-Channels• 9-6 •
The H.110 Basic Rate ISDN Board
using the “SX” command or if this had been done by a timeslot assignment
program associated with a driver, the transmit timeslot portion of this
command will be ignored and the reserved timeslot will be used. In
addition to two-way connections, one-way connections are also possible in
either direction. The Audit command “CA” is used to create a connection
from a timeslot to a port. This command takes the form CAxxsstt, where
xx is the B-channel number, ss is the stream, and tt the timeslot of the
timeslot being audited. As an example, CA000201 would direct timeslot 1
of stream 2 to B-channel 00.
The Transmit command “CX” is used to setup a B-channel to transmit
towards the H.110 bus. This command takes the form CXxxsstt where xx
is the B-channel number, ss is the stream and tt is the destination timeslot.
As an example of using a B-channel as an input, if B-channel 01 is to
transmit on timeslot 5 of stream 6 the command CX010605 would be sent.
A connection will be broken by a Disconnect command. The Disconnect
command “CDxx” will disable the B-channel output and any H.110 bus
connection. An idle state change message “SIxx” will signal that the B-
channel has returned to the idle state. .
A Hold or other B-channel command, such as playing a call progress tone,
will also break a connection. The Hold command “CHxx” will disable
audio to and from the B-channel. If the B-channel was connected to the
H.110 bus, a silence pattern will be output to the H.110 bus. This pattern
can be disabled by a “CDxx” command. It will also be cleared if a connect
or disconnect command is issued for the B-channel.
9.4.2 Call Progress Tones
The on-board DSP can be used to play any of the standard Call Progress
tones to a B-channel. The tones supported are dial tone, busy tone, reorder
tone, and audible ringback. Silence and a calibration tone of 1004 Hz. can
also be played. The Call Progress command “CP” is used to play tones.
This message is of the form CPxxt, where xx is the B-channel and t is the
code of the tone. For example, the command CP002 will play busy tone to
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