Description:
The PK-3, E-12 is a 12 Key DTMF Encoder
The PK-3, E-16 is a 16 Key DTMF Encoder

Sealed Gold Dome Contacts and Steel Keys are the most reliable contact system available to tolerate high & low temperature extremes over a prolonged period of cycling. This is a demand that rubber keys cannot provide.
The PK-3, 12 and 16 key series consist of a high quality keyboard and a miniature electronics circuit. They offer the choice of mounting the electronics directly behind the keyboard or in a remote location apart from the keyboard, without being subject to RFI. Flex cable is an option for remote mounting.

Mounting:
The PK-3, 12 and 16 key series is supplied with mounting template and all necessary hardware for installation.
A. Using the template, carefully select the encoder position.
B. After the position has been selected, pre-punch the object using the template as a guide. Drill carefully for the screws and cut out the hole for the miniature electronics.
C. Use the stainless screws supplied (2/56″ x 1/4″) for fastening. Do not over-tighten.

Power Connections:
• PK-3, 4-16 VDC @ 1 ma stby. 6 ma keyed @ 8V
• Shield: Negative
• Black: Audio Out
• Red: Positive

Output:
Connect the audio output (black) to the microphone or audio input of the transmitter.
Output level to the transmitter is adjusted by the trimpot on the board.
To adjust, use a miniature tool of the proper dimension.
Output level is more than adequate to drive most transmitters. If more level is necessary bridge R3, the 51K ohm resistor with a 1K ohm.
Maximum output is +2dB @ 600 ohms (3V PP)

• PIN 10 of the IC (eyelet +, on PC) will sink a max of 1 ma with voltage drop of .2v w/ 3.5v supply @ pin 1.
• PIN 15 of the IC is used as a STI (single tone inhibit).
To enable the STI cut the PC circuit from pin 15 to pin 1 on circuit side.
UNIT IS NORMALLY STI OFF (PC NOT CUT).
• PIN 16 of the IC is Audio. A + Voltage is available for external drive. Use a diode for isolation (1N914).
Voltage output is 3-4v @ 1ma, w/7-9v @ Red Wire.

Although encoder output frequencies differ by a small amount, it will function properly and reliably because it is within the maximum Bell tolerance of ±1-1/2%

Service:
Do Not use spray or contact cleaners. Contacts on the Keyboard are sealed. To clean, use only a damp cloth. All parts of the Pipo Encoder are replaceable. If repair or replacement is necessary, please contact us via e-mail or telephone, we will instruct you for the best method of return, give us a description of the problem to better serve you.

Level Setting:
NOTE: Not all transmitters have an audio gain control.

1. Set the IDC or deviation control to ±5KHz. This is done by driving the transmitter into limiting by a loud whistle or tone at the microphone.
Transmitter will not go higher than 5 KHz after the deviation is set to ±5KHz. Do not touch or disturb IDC or deviation control after it is set.
2. Some transmitters have an audio gain adjustment (do not confuse with the deviation control).
Set this for your situation, depending upon background noise and your voice and microphone characteristics.
3. To set Encoder Output Level after all previous steps have been completed:
Key transmitter, touch No. 2 and set output level control so the transmitter deviates ±3KHz. Your transmitter is now properly set.
Note: For operation through a 2/3 system where tones will be repeated, set tone for 2.4KHz deviation.