|
|
||
|
"Hello"... meet BUSYER-7Z. The BUSYER-7Z is an educational telephone line busy indicator kit. It lets you know if someone else is on the phone, line in-use (line is off-hook) before you picking up. Large bright LED will indicate the phone line in-use status. No more “Ops,” “I’m sorry,” “I didn’t mean to interrupt,” “I’m on the phone.” The BUSYER-7Z will light when the phone line is off-Hook. It will ends interruptions by indicating that you are “On the phone.” The BUSYER-7Z makes it easy to know that when the phone-line is free. Additionally when sharing one line for both, fax machine and a telephone, the BUSYER-7Z will show you when the line is free again without disrupting an incoming fax.
Note: please be advised, that the BUSYER-7Z is intend for educational purpose only, you will need to obtain fully written approval from your phone service provider company prior to connect any device to the phone lines. This kit doesn't have any industrial approval such as FCC part 15, UL, CE etc. Use it on your won risk. The kit designed to senses the voltage drop on a phone line. The line voltage drop when line is taken off-hook (the line is been use). You can connect the BUSYER-7Z anywhere on the line. The BUSYER-7Z power directly from the phone lines, NO NEEDS FOR EXTERNAL BATTERY OR REGULATOR.
The dual RJ11 connector which included in this unique kit, makes it easy to use. Simply connect the line-plug on one RJ11 jack, and the phone on the other. NO NEEDS FOR EXTERNAL LINE SPLITTER.
Kit Includes
Application-note
Schematic
Regardless of the line polarity (Tip Ring polarity), D1 and D4 ensuring that the top rail (TP1) is always positive, while D2 and D3 ensuring the bottom rail (TP2) is always negative. The transistor Q1 is "on" via voltage divider (RA, RB & R12) while the phone line voltage is high (not in use). The voltage on R12 is enough to turn Q1 "on" about 600 to 800mV. Therefore, Q2-Q4 are "off," therefore L1 (status LED) is off. When the phone line is used (off-hook), the line voltage drops. therefore the voltage on R12 drops. consequently Q1 turns off. Q2 base voltage rise, therefore Q2 & Q3 are turn on. Q2 base current via RA + RC is amplified via Q2, Q3 and Q4, so that Q4 is able to pass enough current to light the L1. Correspondingly Resistors R11 and R5 limit the maximum current amplification of Q2-Q4. Additionally, Q2, Q3 and Q5 must withstand the full line voltage which during ringing while the LED is off, can peak over 200V. This voltage can very depending on the distance from the switch. Finally Q5 limits the current through Q4 to give a constant LED illumination regardless of the phone line voltage about 1 to 1.5mA. The circuit design to slightly dim the LED during ringing.
Always disconnect the circuit from the line before working on it. Testing the kit prior to line connation is very simple: Connect the circuit to a 9V or 12V battery or simulator. Flip battery polarity the LED should light in both cases. With the battery connected, check for about 600 to 800mV on TP3. That all "happy phone-line status monitoring." Final tweak, if the LED remains on even when the line is on-hook, increase R12 (Voltage TP3 decrease). If the LED remains off even when the line is off-hook, decrease R12 (Voltage TP3 increase).
|
||
|
Description and SKU# |
Price |
Picture |
|
Telephone line status LED EID-K-BUSYER-7Z-ASM Fully assembled EID-K-BUSYER-7Z-KIT Kit |
39.00 27.99 |
|
|
EID-K-BUSYER-7Z-PCB PCB Only |
12.99 |
|
|
|
||
