Operating instructions

Digital Telephone Hybrid
Establish a telephone call (the BASIC OPERATION chapter tells how to do this), preferably to an actual person,
group or location to which this TH3 will typically connect. If this is not possible, a call may be placed to a recorded
message service.
Press both TELEPHONE RECEIVE VOLUME buttons simultaneously to reset the user telephone receive volume to
its default setting (0 dB).
Adjust the TELEPHONE RX LEVEL control so that the red led on the RX LEVEL meter lights only occasionally. An
active telephone connection will also be required for step 4, below, so you might not want to disconnect just yet.
Note: It is common for the dial tone and other signaling tones to be louder than normal speech levels. Particularly if
the receive AGC is not used, the dial tone may read off the scale of the RX LEVEL meter when the TELEPHONE RX
LEVEL is set correctly for speech. This is normal and does not require a reduction in the level setting.
3. CODEC RX LEVEL, CODEC TX LEVEL
If the four wire codec interface portion of the TH3 will be used, it is necessary to set the CODEC RX LEVEL and
CODEC TX LEVEL controls.
Establish a connection using the four wire codec (the BASIC OPERATION chapter tells how to do this).
Press both CODEC RECEIVE VOLUME buttons simultaneously to reset the user codec receive volume to its default
setting (0 dB).
Adjust the CODEC RX LEVEL control so that the red led on the RX LEVEL meter lights only occasionally. Adjust the
CODEC TX TRIM control for proper level as required by the codec. If the codec provides no level indication, in most
cases setting the CODEC TX TRIM approximately the same as the CODEC RX LEVEL control will suffice.
4. LecNet ANTI-ECHO [with Lectrosonics Mixers only]
If your installation uses a Lectrosonics mixer which is connected via the TH3’s LecNet Expansion Out jack, use this
procedure to set the LecNet ANTI-ECHO control.
With a connection established (either telephone or codec), have someone speak normally into a local microphone
and take note of the behavior of the LecNet ANTI-ECHO meter. Next, have the remote party speak, and adjust the
LecNet ANTI-ECHO control until the deflection of the LecNet ANTI-ECHO meter is approximately equal to that
caused by the local signal.
Note: Exactly where to set the LecNet ANTI-ECHO control is largely a matter of preference. If it is set too low, the
remote party may hear objectionable echoes immediately after speaking. If it is set too high, local speakers may
have difficulty interrupting the remote speaker. In most cases, setting the control for equal meter deflection, as
above, yields excellent results.
TH3 SOFTWARE CONTROL PANEL
Some of the TH3’s more advanced features may be accessed only via the serial port. A convenient software “control
panel” for the TH3 is included in the LecNet Master Pro software package. The TH3 software may be run alone as a
demonstration of the TH3’s features, or via LecNet Master Pro for live control of a TH3. The TH3 software control
panel permits easy access to all TH3 features, as described below.
Installing the Software
To install LecNet Master Pro, insert the LecNet Master Pro disk and run SETUP.EXE from the disk.
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