Copy Link
Add to Bookmark
Report
Phuk Magazine Issue 01 Phile 06 of 10
=============================================================================
PHUK MAGAZINE - Phile 6 of 10
=============================================================================
-----------------------------
Simple Line Monitor - TheGoat
-----------------------------
The simple line monitor provides a number of functions, initialy it
was produced to give a visual indication of ringing.
Parts : Line connection jack & cable.
Two led's, green and red.
Two resistors 33K.
Small piece of vero.
For convenience I used a ready molded phone jack cable scavenged from
an old phone, I also found it had a .1" pin socket on the other end,
the plug for which was also removeable from the phone, mounting the
plug at one end of the vero, I put the resistors and LEDs in the
middle to form a small square.
1 +----------------------+
2 +------\ +----+ ==+2-\-R1----D1+----+ |
3/4 |P/jack]+----//--| + ==+ \--R2----+D2--+ |
5 +------/ +----+ ==+5----------------+ |
6 +----------------------+
Effectivly, pin 2 of the phone jack connects to both resistors each
resistor to a diode, note positive of each diode. and finaly both
diode ends lead back to pin 5 of the phone jack.
Pin 2 ------------------+-------+
| |
R1 R2
| |
+ |
D1 D2
| +
| |
Pin 5 ------------------+-------+
The connection of pin 5 and 2 is not too important.
When connected to a line one LED will be lit to show line voltage,
if a ring signal is present both LEDs will light brightly in the ring
pattern. (ie: flash-flash--blank-blank-..... etc). As such this met
the initial requirements, but when we first tried it in anger we
found it could also indicate a number of other things. When a phone
is also attached to the line and is picked up the single LED will dim
to about half its previous brightness. If a futher phone is added,
then when the second phone is picked up a futher dimming is noticable.
When tapping a line, indication that the destination phone is in use is
important.
Coming in the next article: Upgrading to give a direct connection to
a computer port for Ring Indication.
- TheGoat
+++
EOF
