Notes from Customer Service

How to set up a 930A Communications Test Set to generate DTMF digit strings of desired amplitude and on/off times, for connection to an external recording device

Setting the Trunk Type to a 4-Wire 600 ohm Analog Metallic Interface [Trunk Type Setting]

1. Press the Trunk Type button (top black button at the left of the front panel) three times, then press the up or down arrow key (located at the bottom left of the display) to cycle through the various trunk types until you see a display similar to the following: NORMAL LOOP BRIDGE CONTACT 2W 900

2. Repeatedly press softkey 4 (located directly under "2W 900") until you see "4W 600".

3. If "BATTERY" is displayed instead of "CONTACT", change it to "CONTACT" by pressing softkey 3 (located directly under "BATTERY") once.

4. Press softkey 2 (located directly under "BRIDGE") to change it to "TERM".

Setting the 930A's TLP (Test Level Point) [Menu Option 30 - Adjust TLP]

Note: Adjusting the TLP level sets the reference point for DTMF and certain other levels. Using Menu Option 1 (Modify Dial Ring), you can then change the DTMF levels with respect to that reference. This section covers setting the 930A transmit and receive TLP's to 0 dBm.

1. Press the Option Menu button (bottom black button at the left of the front panel) three times.

2. Using the numeric keypad, enter the number "30", then press any one of the softkeys under the display once. You should see a display similar to the one below: ADJUST: SEND TLP RECV TLP

3. Press softkey 1 (directly under "SEND TLP"). You should see a display similar to the one below: SEND TLP: LOCK? -16dBm DEFAULT EXIT

4. Press softkey 2 (directly under "-16dBm"). Then, use the numeric keypad to enter "0", and finish by pressing softkey 2, again. You should see a display similar to the one below: SEND TLP: LOCK? +0dBm DEFAULT EXIT

5. Press softkey 1 (directly under "LOCK?") to insure it doesn't change, then press softkey 4 (directly under "EXIT"). This should return you to the "ADJUST" display as illustrated below: ADJUST: SEND TLP RECV TLP

6. Press softkey 3 (directly under "RECV TLP"). You should see a display similar to the one below: RECV TLP: LOCK? +7dBm DEFAULT EXIT

7. Press softkey 2 (directly under "+7dBm"). Then, use the numeric keypad to enter "0", and finish by pressing softkey 2, again. You should see a display similar to the one below: RECV TLP: LOCK? +0dBm DEFAULT EXIT

8. Press softkey 1 (directly under "LOCK?") to insure it doesn't change, then press the Option Menu button (bottom black button at the left of the front panel). This will exit the function and return you to the "OPTION MENU" display as illustrated below: OPTION MENU #: 30 ADJUST TLP

Adjusting DTMF Digit On/Off Timing [Menu Option 1 - Modify Dial Ring]

Note: The digit on-time and off-time affects all digits, and must be set prior to using the Dial/Ring function to store digit strings. The maximum allowed value for on- and off-times is 9999 milliseconds; the minimum is 10 milliseconds.

1. Press the Option Menu button (bottom black button at the left of the front panel) three times.

2. Using the numeric keypad, press the digit "1", then press any of the softkeys under the display once. You should see a display similar to the one below: MODIFY: LEVEL FREQ TIMING

3. Press softkey 3 (directly under "Timing"). You should see a display similar to the one below: 50 ON 50 OFF DEFAULT EXIT

Note: The above display indicates that, in a string of transmitted digits, each digit will be "on" for 50 milliseconds, and "off" for 50 milliseconds.

4. To modify the digit "on" time, press softkey 1 (directly under "50 ON"), enter the desired on-time in milliseconds, then press softkey 1 again.

5. Similarly, To modify the digit "off" time, press softkey 2 (directly under "50 OFF"), enter the desired off-time in milliseconds, then press softkey 2 again.

Adjusting DTMF Levels [Menu Option 1 - Modify Dial Ring]

Note: Because you have previously selected a trunk type exhibiting 600 impedance and you have set the 930A to 0 TLP, (and presuming the load impedance is also 600 ) the levels you specify in this section are always expressed in dBm units.

1. Press the Option Menu button (bottom black button at the left of the front panel) three times.

2. Using the numeric keypad, press the digit "1", then press any of the softkeys under the display once. You should see a display similar to the one below: MODIFY: LEVEL FREQ TIMING

3. Press softkey 1 (directly under "LEVEL"). You should see a display similar to the one below: -7.0dBm -7.0dBm DEFAULT EXIT

Notes: 1. The left value is the current setting for DTMF low-side tones, the right value is for the high tones. The value of -7.0 is used as a default because telephone companies typically expect each of the tones in a DTMF digit to be transmitted to them 7 dB below the TLP for that circuit. Note also that, when the output is measured with a true RMS voltmeter, the resulting composite signal (made up of two equal level tones) is 3 dB higher in amplitude than either tone individually).

2. Unless you wish to purposely introduce "Twist" (unequal levels in the tone pair), make both tones equal in level.

4. To change the level of the low-side tone, press softkey 1 and use the numeric keypad to enter the level you desire. The allowable range is -60.0dBm to +12.0 dBm. To create a positive dBm level, enter the desired digits, followed by pressing the "+/-" ("D") key at the bottom right of the numeric keypad.

5. After entering the digits (and +/-, if desired), press softkey 1 to store the level.

6. Repeat the sequence for changing the level of the high-side tone: press softkey 2 and use the numeric keypad to enter the level you desire, then press softkey 2 to store the level.

7. Press the Option Menu button (bottom black button at the left of the front panel) to exit the function. Seeing a display similar to the one below confirms you've exited the function. OPTION MENU #: 1 MODIFY DIAL/RING

Verifying "Skew" is at 0% [Menu Option 1 - Modify Dial Ring]

Note: "Skew" is a term which indicates how much off-frequency each tone is. Unless you wish to purposely introduce "Skew" (change the frequency of the low and high tones by a % amount) make sure the percentages are 0.0%.

1. Press the Option Menu button (bottom black button at the left of the front panel) three times.

2. Using the numeric keypad, press the digit "1", then press any of the softkeys under the display once. You should see a display similar to the one below: MODIFY: LEVEL FREQ TIMING

3. Press softkey 2 (directly under "FREQ"). You should now see a display similar to the one below: +0.0% +0.0% DEFAULT EXIT

4. If either of the values are not 0.0%, press the softkey directly under the offending one, then enter a "0", followed by a pressing that softkey again.

5. Press softkey 4 (directly under "EXIT"), then press the Option Menu button to exit the function.

Storing a String of Digits for Transmission [Dial/Ring Function]

After you have set the Trunk Type, TLP, digit on/off timing and digit tone levels you can proceed to store digits for transmission. Note: You can store a digit string with one set of on/off timing and tone levels in one register, then change the parameters and store digits with the new parameters into register 02, another set in register 03, etc. Doing this would allow you to quickly "RCL" (recall) different sets and transmit them, using Menu Option 2 (Send Digit Sequences).

1. Press the Dial/Ring button (2nd black button from the top, at the left of the front panel). You should now see a display similar to the one below: RPT? DTMF TR

2. If there are any digits to the left of "RPT?", press the grey "CLR" button located at the right of the numeric keypad.

3. If "MF" or "DP" is displayed instead of "DTMF", slowly and repeatedly press softkey 3 until "DTMF" is displayed.

4. Using the numeric keypad, key-in the digit string you wish to use.

5. Now, store this string in register 1 by doing the following: A. Press the grey "STO" key (located just to the right of the numeric keypad) B. Then use the numeric keypad to enter the digit "1" C. Finally, press the grey "ENT" key to execute the store function.

Transmitting a Stored Digit String [Menu Option 2 - Send Digit Sequences]

1. Press the Option Menu button (bottom black button at the left of the front panel) three times, then use the numeric keypad to enter the digit "2"; now, press any one of the softkeys under the display. You should see a display similar to the one below: AUTO REPEAT? YES NO

2. Press softkey 4 (directly under "NO"). You should now see a display similar to the one below: WINK OFF-HK MORE

3. If there are any characters to the left of "WINK", press the grey "CLR" key (at the right of the numeric keypad).

4. To select (for transmission) the DTMF digit string you previously stored in register 1, enter a "1". Your display should now look like the one below: 1 WINK OFF-HK MORE

Note: To select a digit string stored in register 2, simply enter a "2" instead of "1".

5. To transmit those digits out of the front panel "TR" jack, simply flip the On/Off Hook switch into the Off Hook position.

Note: If you desire accurate transmit levels, insure the device connected to the TR jack represents a 600 ohm resistive load, to match the 930A's 600 ohm source impedance that you setup using the Trunk Type button.

Thank you for doing business with Sage Instruments. If you have any questions or comments about this note, please call Sage Instruments Customer Service at (831) 761-1000.