Ericsson LBI-39101A User Manual
Page 7
BOARD SET-UP
LBI-39101
7
Digital Pots Settings
To provide computer-controlled level settings, the
Enhanced Audio Enclosure's audio input and audio output
circuits incorporate 256-position digitally-controlled
potentiometers. These digital pots, located on the Audio
System Board, allow adjustment of the Enhanced Audio
Enclosure's audio levels via the PC. Adjustments include
dispatcher-adjustable audio levels such as headset sidetone
volumes and system-level adjustments such as line input and
output levels to and from the CEC/IMC Digital Audio
Switch.
With the exception of the dispatcher's headset sidetone
volume adjustments, none of the digital pots provide volume
adjustments for the speaker or headset earphone audio levels
during normal dispatch operations. Speaker and headset
volume adjustments are accomplished at the respective
speaker or headset via mechanical pots. Also see the
following note.
Communication module volume changes at the C3
Maestro effect CEC/IMC CIM line output levels,
not the digital pots within the Enhanced Audio
Enclosure.
Fifteen (15) dual digital potentiometer chips (integrated
circuits) are located on the Audio System Board for a total ↑ > and ↓ > at the Dispatch Keyboard. All of the digital pots initially power-up with the wiper in a 50% or centered position. The microcontroller on the Digital pots may be adjusted using the C3 Maestro application program via one of its note cards. This function after the console's installation is complete and it has been powered-up: 1. From the Dispatch Keyboard, simultaneously press the numeric keypad) keys. " Digital Pot Number: ? " is displayed in the lower left-hand side of the C3 2. From the numeric keypad, enter the number of the digital pot to be changed. See Table 3. The digital 3. Press the ↑ (increase) or ↓ (decrease) key to change the current setting. Changes are saved in the 4. Press SPEAKER ASSEMBLY Normally, a Speaker Assembly used with the Enhanced Audio Enclosure is configured at the factory with its The following information lists the normal factory Speaker Amp Board At each Speaker Assembly, a 4-position DIP switch identified as SW1 is located on the Speaker Amp Board. NOTE SW1 may have a tape seal placed over the switches Minimum Volume Level DIP Switch (SW1 Position 1) When SW1 position 1 is " OFF " or " OPEN ", the minimum volume level feature is enabled. This is the factory NOTE NOTE NOTE
of thirty (30) individual pots; there are no mechanical
potentiometers. All audio level adjustments are
accomplished via software. See Table 3. A dispatcher may
adjust the operator's sidetone digital pot using dedicated
keyboard keystrokes
Audio System Board then immediately loads each pot in
accordance with its respective setting stored in a "working"
area of a serial EEPROM chip on the board. The EEPROM
also contains an unchangeable "default" digital pot storage
area. When shipped from the factory, the working area
matches the default area.
changes the settings stored in the EEPROM's working area.
Normally, this note card function should only be accessed
by the installation and/or service personnel. To change a
digital pot's setting, the following procedure may be
performed
Maestro's display.
pot's existing setting is displayed.
EEPROM's working area as they are made.
minimum volume feature enabled and its maximum volume
output power set to 2 watts. This configuration is
accomplished by setting two positions on a 4-position DIP
switch located on the Speaker Amp Board within the
Speaker Assembly.
settings and the optional settings which are
available.
One position is used to enable or disable the minimum
volume level feature. A second position allows setting of the
maximum volume level to either 2 or 5 watts of output
power. Factory settings are shown in Figure 3. These
switches have no effect on headset earphone output levels.
Currently, the other two DIP switch positions on SW1 are
not used.
to prevent changes.
setting. With this setting, audio from the speaker cannot be
completely turned off by rotating the volume control on the
Speaker Assembly's front panel fully counterclockwise.