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- -------------------------------------- --------------------------------------
- - The Conference Box - - By: Madd Max -
- -------------------------------------- --------------------------------------
-
- What is a Conference Box?
-
- After hooking a conference box on your line you can talk on two lines at
- the same time. Therefore, if you already have 3-way on both lines, you could
- talk to 4 people at the same time (5-Way...). This version works (Unlike that
- box you can 'PICK UP' at Radio Shack...).
-
- What do I need?
-
- Item Description
- ---- -----------
- C1 10-uF, 50-volt electrolytic capacitor
- C2 Another 10-uF, 50,volt electrolytic capacitor
- C3 10-uF, 15-volt tantalum capacitor
- R1 10K, 1/4 watt, 10% composition resistor
- R2 100-ohm, 1/4 watt, 10% composition resistor
- Q1 2N3904 npn silicon transistor
- S1 Dpst toggle switch
- S2 Another Dpst toggle switch
- T0 Telephone coupling transformer, Microtran T2110 or equivalent
- Some wire or a circuit board (Design your own)
-
- Some electronic equipment
- A box
- A little patience
-
- Notes:
-
- The 'Item' is used to indicate where it goes in the diagram. You can use
- any transformer which is rated at about 900 ohms both primary and secondary,
- over the frequency range of about 300 to 3000 Hz.
-
- How does everything go together?
-
- + / C1 C2 / +
- ----,----* *------*------$-----@ @---------$----*----*----* *----------,-
- Line 1 ' ! + @ @ + ! ! ' Line 2
- ' ! @ @ ! R1# '
- ' ! @ @ ! ! '
- S1 ! @ @ \: ! S2
- ' Telephone @T0@ Q1 :--* '
- ' Set @ @ /: ! '
- ' ! @ @ ! !+ '
- ' ! @ @ R2# $C3 '
- / ! @ @ ! ! /
- ---------* *------*------------@ @--------------*----*---* *-------------
-
-
- What did all that mean?
-
- Symbol Meaning
- ------ -------
-
- - Horizontal Wire
-
- ! Vertical Wire
-
- * Point where wire splits, separates, merges, etc.
-
- /
- * *
- '
- '
- ' A Dpst toggle switch
- '
- '
- /
- * *
-
- $ Capacitor
-
- # Resistor
-
- @ To the Transformer
-
- + Positive end (of line or capacitor)
-
- - Negative end
-
- \:
- :-- Transistor
- /:
-
- How do I use it?
-
- Pick up the telephone set and flip the first switch on. You should get a
- dial tone. Dial someone and tell them to hang on. Flip the second switch and
- you should get another dial tone. Dial another number. After they answer, you
- should be able to talk to both of them and they should be able to talk to one
- another. If you have 3-Way on one (or both lines) you can flip the switch
- corresponding to that line on and off (RAPIDLY) to switch the 3-Way.
-
- NOTE: Because you went to all the trouble of making this with a transformer, it
- should sound PERFECT!