Following are the input connection options for the T21 Transmitter:
“Balanced Audio Input” Concentric Jack:
Accepts balanced XLR or TRS 1/4” Mic-Level or Line-Level Inputs
Accepts unbalanced Mic-Level or Line-Level Inputs
Accepts unbalanced Speaker-Level Inputs (25V, 70V speaker line)
See the diagram on the next page for connection details.
“Unbalanced Audio Input” Screw Terminals:
Accepts one to three unbalanced line-level signals, which are actively mixed.
The three inputs share a common ground connection.
Use the audio cable and adapter supplied to connect the T21 "Audio In" jack to an appropriate
audio output jack on the sound system mixer or amplifier. If your amplifier or mixer does not have
RCA-type connectors, you can obtain adapters from your Williams Sound Authorized Dealer or a
local radio parts store. If the TAPE OUT jack is already in use, a Y-Cord can be used to connect the
T21 and a second device to the same jack.
Step 4. Set the Input Selector Switch
If you are using the combination XLR/phone plug input jack, make sure the selector switch is set in
the proper position as shown above.
Step 5. Set the Hi-Pass Filter Switch
The High-Pass Filter switch is used to reduce low frequencies. It is normally used in the middle (175Hz)
position to provide high frequency emphasis that improves speech understanding. If the program
content is primarily musical, it can be used in the left (20Hz) position. The right position (725Hz) may
Sound System Amplifier
Loudspeakers
Microphones
T21 Transmitter
Line-Level Output
FM Pocket Receivers
with Earphones
Balanced Audio Input
Line
Mic
70V
FM Auditory AssistanceTransmitter
Select
Unbalanced
Audio Inputs
20 Hz
175 Hz
725 Hz
Hi-Pass Filter
Antenna
Power: 24 VAC, 60 Hz, 10VA
RF Power
75 Ohm
Made in USA
Williams Sound Corp.
Channel
COM
IN 1
IN 2
IN 3
-12dB
Max
-6dB
1st
Digit
2nd
Digit
Use with TFP 016 Power Supply
0
1
Overall System Diagram
Page 5
RCA to 1/4" Adapter
To T21 Concentric Jack
RCA to RCA Cable
From Sound System Line Output
Using the Audio Cable Supplied with the System
