rv01@gte.com (Robert Virzi) (12/01/89)
On a topic slightly different than visual indication of a ringing phone, I would like a box that indicated that the phone connected to it has rung (past tense). Here's why: We have an automated answering service at work. This service picks up after a certain number of rings or on busy. The caller can leave a message, which is then placed in the called parties mailbox. The standard dialtone is then changed to stutter dialtone, to indicate a waiting message. So upon return to my office, I have to pick up the phone (and login to a unix machine and check the lan-based mailer and ... )-: ) to see if I have any messages pending. Naturally, I don't always remember to do this so I am occassionally later in returning calls than I would like to be. However, if their were a box next to my phone that lit up on a ring, and *stayed lit up* until reset, I would have a better chance of noticing and retrieving my messages in a timely manner. My first question is, does such a box exist as an off-the-shelf item? If not, does anyone have a circuit that would do this? Perhaps a mod to the various boxes suggested for visual ringing indication??? Better yet, does anyone know of a box that would periodically check my phone line and light up on detection of stutter dialtone? This would be the preferred solution as it would (a) not have to be reset manually, (b) would not false alarm if no message were left, and (c) would also catch those messages left on busy (when I'm already on the phone). Ideally, I would like to be able to set the frequency with which the line is sampled for stutter dialtone. Bob Virzi | Innuendo ... rv01@gte.com | ...!harvard!bunny!rv01 | ... and out the other.
Ken Thompson <kthompso@entec.wichita.ncr.com> (12/05/89)
It sounds exactly like the ATT system we have at work. You can buy an analog phone that has a little message led that flashes once a second when there is a message. This is in addition to the sudder dial tone. Your old phone can do the job. Put an led in series with a 22K resistor across your phone line. Get the polarity right so that the led lights when the phone is ON HOOK. When you have a message the led will blink off momentarily once a second. It will flash brightly when the phone rings and when you are off hook it will go nearly out. Have fun. PS. This is being used all over our building. Ken Thompson N0ITL NCR Corp. 3718 N. Rock Road Wichita,Ks. 67226 (316)636-8783 Ken.Thompson@wichita.ncr.com
dave@uunet.uu.net (Dave Levenson) (12/06/89)
In article <1813@accuvax.nwu.edu>, kthompso@entec.wichita.ncr.com (Ken Thompson) writes: > It sounds exactly like the ATT system we have at work. ... > PS. This is being used all over our building. No, Ken, that works all over your building because your building is served by a PBX or other switching system that offers a message-waiting notification feature. Normal central office subscriber lines will not control the message-waiting lamps on your telephone sets. Dave Levenson Voice: (201) 647 0900 Westmark, Inc. Internet: dave@westmark.uu.net Warren, NJ, USA UUCP: {uunet | rutgers | att}!westmark!dave [The Man in the Mooney] AT&T Mail: !westmark!dave
John McHarry <m21198@mwvm.mitre.org> (12/07/89)
I haven't had a chance to build this yet, but: Most US subscriber loops have about -52v on the ring and ground on the tip when on hook. When off hook, the voltage drops to something less than 8-9 volts. Ringing is accomplished by superimposing a nominal 86v rms on the -52v ring-tip voltage. An indicating device that turned on at something greater than 52v would accomplish the task, if it could be kept on by an external power source or by the 52v on hook voltage, the latter requiring very low current draw to avoid appearing off hook. As I recall, a device that can do this is the old NE-2 neon bulb. It requires something over 80? volts to turn on, but can be kept lit by well under 1 ma. The bulb, in series with a 100k resistor should be put in series with a diode good for at least 200v. Put about a 2 micro farad cap across the resistor and lamp part of the circuit. Hang the whole thing across tip and ring with the cathode end of the diode hooked to ring. If the lamp is so sensitive as to light with just the 52v, a 100-200k resistor across the lamp should solve the problem. The diode and cap are in the circuit to keep the positive cycle of the ringing voltage and short interruptions of the 52v from extinguishing the lamp. Taking a phone off hook should automatically extinguish the lamp by interrupting the -52v long enough for the cap to discharge. As I said, I have yet to build this, but it should work. It may be subject to some falsing due to lightening, etc. Also, it should be checked for immunity to 'dial tap'. It will indicate an incoming call attempt, but not whether there is voice mail, of course. (The usual disclaimers)**2 and do be careful, a telephone line can bite like a light socket...remember the apocryphal dog. *************************************************************** * John McHarry (703)883-6100 M21198@MWVM.MITRE.ORG * ***************************************************************
toddi@gtisqr.UUCP (Todd Inch) (12/07/89)
I want to reply to the person who wanted a light to tell him if the
phone rang (and therefore he probably has voice mail) while he was
away. (Sorry, I lost the original article, please forgive my vague
reference.)
About a week ago I submitted an article on how to make your phone bell
into a ringer. If you do that, or use some other relay-type device,
it should be easy to make the lamp stay on with the following circuit.
Get a relay which will operate on the same voltage as the lamp you
want to power. A common normally-open single-pole single-throw type
will probably do (see note at end.)
Connect the contacts of the ringer-relay (operated by the phone
ringing), the power supply (or possibly battery if you use an LED),
and the coil of the new relay in a series circuit. Now the first
relay will operate the second relay when the phone rings.
Now connect the contacts of the second relay across (in parallel with)
the contacts of the first relay. This allows the second relay to
"turn itself on" and the ringer-relay can also still turn it on. When
a pulse through the ringer-relay operates the second relay, the second
relay will keep itself on after the pulses have stopped. This is a
simple latch which I've also used for burgalar alarms.
Connect the lamp in parallel with the coil of the second relay so it
is also turned on and kept on.
Install a normally closed (normally "on") switch in series with the
power to the circuit (or just an on-off power switch.) This will
reset the second relay and lamp by momentarily disconnecting the
power.
It may be necessary to add a diode (rated between 1 and 15 amp and at
least twice whatever voltage you're using) in parallel with the second
relay coil and the lamp. Be sure the Cathode (striped end) is
connected to the Positive side of the coil and the Anode is connected
to the Negative side, which is backwards from the way they are usually
connected. This will effectively stretch the pulses by using the
coil's inductance to keep its current flowing after the pulses have
stopped. This is assuming you're using DC power.
If you do have a second pair of contacts in the relay, I'd use those
for the lamp circuit, disconnecting the lamp from the relay coil.
This may be necessary if the lamp draws lots of current.
If you use an LED (light emitting diode) with a series 220 ohm to 2K
ohm resistor (depending on the voltage) as the indicator lamp, you
shouldn't need the diode across the coil and you won't need to worry
about the lamp current draw.
Also - regarding my previous suggestion for turning a WECO-type bell
into a ringer-relay, you MAY be able to place the reed switch in the
right spot on the frame or near the magnet or somewhere so that the
ringer is still intact (and therefore rings) but also operates the
reed switch, although I haven't tried it. The switch may provide
pulses which are too short if the magnetic field at that location is
too weak.
I hope I haven't made this sound too complicated, it really isn't, but
let me know if you want more info. Hope this helps.
Todd Inch, System Manager, Global Technology, Mukilteo WA (206) 742-9111
UUCP: {smart-host}!gtisqr!toddi ARPA: gtisqr!toddi@beaver.cs.washington.edu
"You are the booger in the nose of my life." - My wife, to me. (Jokingly?)
Disclaimer: My boss will read this while checking up on me and will disagree.