Description

TF-204 2-Wire/4-Wire Interface

Two channel or 4 channel is optional

Input and out Level adjustment

The TF-204 4-wire interface is consisting of two units. Each unit has two independent sets of 2-wire / 4-wire connectors.

Front Panel

l Sidetone Adjustment

Unsatisfied sidetone could cause feedback between input and output. In either of these cases, you should minimize the amount of sidetone.

Sidetone Adjustment Procedure:

A) Set Link (5) switch to OFF.

B) Turn the Input Level Reduction Switch (8) to 0dB.

C) Press Test Tone (7) button, a constant beep sound can be heard from the Sidetone (6) Monitoring hole.

D) Adjust Output Level (9) control knob to make the beep level heard properly.

E) Turn the Main Sidetone Adjustment M (1) knob by clockwise and anti-clockwise direction slowly. Find minimum listening level. 

F) Turn the Auxiliary Sidetone Adjustment A (1) knob. Find the minimum listening level.

Repeat this procedure A) to F) for other channels.

l Output Level

Output Level Reduction Switch (8)

This switch has 0dB, -20dB and -40dB three levels. It reduces the signal level which is sent to the pin3 and 4 of 4-wire connector (13) at rear panel.

Output Level Adjustment (9)

This output level adjustment provides a strong average green light on the Output Level Indicator (10). This occurrence indicates a 0dB line level on 600ohm line. Red light indicates exceeded output level. Occasional transitions to a red light are acceptable.

Output Level Indicator (10)

Green light indicates output level normal.

Red light indicates output level high.

l Input Level

Input Level Reduction Switch (2)

This switch has 0dB and -20dB two levels to match the signal level which is sent from pin1 and 2 of 4-wire connector (13) at rear panel.

Input Level Adjustment (6)

Adjust the Input channel gain to fit different input signal level. This knob provides a strong average green light on the Input Level Indicator (4). Meanwhile the level on pin3 of 2-wire connector is 0dB. Red light indicates exceeded input level. Occasional transitions to a red light are acceptable.

Input Level Indicator (4)

Green light indicates input level normal.

Red light indicates input level high.

l Link

Link (5)

Channel A and Channel B are individual to each other when this switch is set to the Off position.

When this switch is set to ON position, Channel A and Channel B are connected.

Rear Panel

4-wire In/Out Connector (8)

Input:   Pin1 --- Audio+

          Pin2 --- Audio- (Common)

Output: Pin3 --- Audio- (Common)

          Pin4 --- Audio+

External signal to TF-204 can be balanced or unbalanced. Unbalanced signal is easier to bring in the noise, it is better to bring in balanced signal.

Intercom Line Connector (9)

3-pin XLR female socket

The pinout of the intercom connectors is as follows:

Pin 1 --- Common (Shield)

Pin 2 --- Power (15~30 VDC)

Pin 3 --- Audio

III. Installation

TF-204 adopts 19-inches 1U cabinet, and this workstation can be mounted on rack or placed on desktop. TF-204 uses standard 2-core shield cable. It can be powered by any channel or by A, B (A, B, C, and D) together.

Two XLR-3 connectors for channel A and B are used to connect 2-wire equipments. Pin connector is used to connect 4-wire input and output equipments.

IV Troubleshooting
Problem: System feedback (Acoustical)

Cause 1: Input or output signal level is too high

Solution 1: Adjust the signal level

Cause 2: Side tone of this station or any remote station is not adjusted correctly

Solution 2: Adjust side tone refer to the procedure in the Front Panel section of this manual.

Cause 3: No terminal in the system.

Solution 3: Check the terminal in the system.

Cause 4: 4-wire equipments connector are not connected well

Solution 4: Check the connection.

Problem: Output level is set to max, the audio level from camera end is still too low

Cause: Output level raw adjustment is not proper

Solution: Set output level raw adjustment to ‘Line’, then adjust output level to proper level

Problem: The audio level heard from camera end is too low

Cause: Input level is too low

Solution: Adjust input level by clockwise to proper level

Problem: Hum or buzz in system

Cause 1: Inductive pickup caused by close proximity of this main station or connected remote stations to power lines or transformers.

Solution 1: Relocate the offending unit.

Cause 2: Intercom line cable is not wired properly; the shield of microphone cable is not connected to Pin-1 of 3-XLR

Solution 2: Check intercom line cable. Make sure all the cables’ Pin-1 of 3-XLR connects correct.

V Technical Specification

Bandwidth:

300Hz – 4000Hz ±3dB

Input:

Balanced, unbalanced self-adaption

Resistance: >10K ohm Bridge

Level:  -37dBu-+12dBu (1KHz)

Output:

Balanced, unbalanced self-adaption

Resistance: 600 ohm 

Level: -43dBu - +8dBu (1KHz)

Environmental

0°-70°C（32°-158°）

Dimensions

19” (W) x 1.77” (H) x 6.69” (D), 483mm x 45mm x 170mm

Weight

1.9kg

Note: 0dBu=0.775V RMS