Phone generator/ringer overcomplicated?
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Posts: 46,084
I need to build a phone ringer (I have the frequency generator).
What is needed is when the operator pushes the buttor the phone
selected, it rings like a real phone untill the receiver is picked
up. I was looking at timer relays but they are about as expensive as
using a stamp and icecube relays. Does this seem right or am I
overdoing it again with a stamp? Any help appreciated.
Ian
What is needed is when the operator pushes the buttor the phone
selected, it rings like a real phone untill the receiver is picked
up. I was looking at timer relays but they are about as expensive as
using a stamp and icecube relays. Does this seem right or am I
overdoing it again with a stamp? Any help appreciated.
Ian
Comments
between rings and control of the relay(s). How are you going to sense
that the reciever was picked up? You can do it from the remote end, but
it will require current sensing if memory serves me.
-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas Office
Original Message
From: iphillipsca [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Wg6ZTlPrM6Sx7mWOnLzParplZSCuyR7NAkKUtlZqrLQZpKZwMGbCGQf-ptlEhSEJMJkGZdmdE7MFp_TB7vg1SLk]iphillips@s...[/url
Sent: Friday, March 26, 2004 10:47 AM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Phone generator/ringer overcomplicated?
I need to build a phone ringer (I have the frequency generator).
What is needed is when the operator pushes the buttor the phone
selected, it rings like a real phone untill the receiver is picked
up. I was looking at timer relays but they are about as expensive as
using a stamp and icecube relays. Does this seem right or am I
overdoing it again with a stamp? Any help appreciated.
Ian
phone to ring. Can't remember if this is a square wav or sine wave, but I'm
guessing a square wave would work. A phone does indeed present a specific
impedance load to the line, around 600 ohms or so. If that's the case (and
I'm pretty sure it's close) you could hook the output of the stamp to drive
a little IC audio amplifier with a 12-volt power supply, or even a FET,
remembering the flyback diode. You can probably get the voltage up to the
needed level with a 10:1 transformer, but you'll have to match the frequency
of the AC wav, which escapes me at the moment. Should be pretty simple once
you verify voltage and such.
And yes, you can get a pretty good shock from the phone line when it rings.
Been there... Done that...
Mike Sokol
mike@f...
www.fitsandstarts.com
" One should not increase, beyond what is necessary,
the number of entities required to explain anything"...
-William of Occam-
Original Message
From: "iphillipsca" <iphillips@s...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, March 26, 2004 11:46 AM
Subject: [noparse][[/noparse]basicstamps] Phone generator/ringer overcomplicated?
> I need to build a phone ringer (I have the frequency generator).
> What is needed is when the operator pushes the buttor the phone
> selected, it rings like a real phone untill the receiver is picked
> up. I was looking at timer relays but they are about as expensive as
> using a stamp and icecube relays. Does this seem right or am I
> overdoing it again with a stamp? Any help appreciated.
> Ian
>
>
>
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Body of the message will be ignored.
>
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>
>
>
>
>
>
>If memory serves, a telephone line puts out around a 100 volt AC swing for a
>phone to ring. Can't remember if this is a square wav or sine wave, but I'm
>guessing a square wave would work.
A >>long<< time ago you use to be able to see 48V battery packs on
tele-poles...
The "ring" was generated by switching polarity effectively creating 96V AC.
A Square wave does work ok, but if I remember correctly this feature (sine vs.
square) is what distinguished the top-of-the-line vs. the knock off TELCO
testers... Radio Shack used to sell one.
> A phone does indeed present a specific
>impedance load to the line, around 600 ohms or so. If that's the case (and
>I'm pretty sure it's close) you could hook the output of the stamp to drive
>a little IC audio amplifier with a 12-volt power supply, or even a FET,
>remembering the flyback diode. You can probably get the voltage up to the
>needed level with a 10:1 transformer, but you'll have to match the frequency
>of the AC wav, which escapes me at the moment. Should be pretty simple once
>you verify voltage and such.
I think that the frequency is 20Hz .... (could always scope your phone line
and call it from another phone)
>And yes, you can get a pretty good shock from the phone line when it rings.
>Been there... Done that...
Nothing like stripping wires (with teeth - dumb kid I was) and having the
phone just happen to ring! Ouch
>Mike Sokol
>mike@f...
>www.fitsandstarts.com
>
>" One should not increase, beyond what is necessary,
>the number of entities required to explain anything"...
>-William of Occam-
>
>
> > I need to build a phone ringer (I have the frequency generator).
> > What is needed is when the operator pushes the buttor the phone
> > selected, it rings like a real phone untill the receiver is picked
> > up. I was looking at timer relays but they are about as expensive as
> > using a stamp and icecube relays. Does this seem right or am I
> > overdoing it again with a stamp? Any help appreciated.
> > Ian
> >
Beau Schwabe Mask Designer National Semiconductor Corporation
500 Pinnacle Court, Suite 525
Home: polygon_man@h... Mail Stop GA1
Work: bschwabe@a... Norcross, GA 30071
have the generator I would only be switching the output of it to
multiple phones. And yes, I have Bin there Dun that too!
Ian
Original Message
From: Mike Sokol [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=G7tVEWpZbZR2bdgitTS7_D2BQkKUzZ-tWQNek_imhLXpEUgbeQlomjVVYfbPN7b_kJ6oLeozkmXAw6hYYPBJ]mike@f...[/url
Sent: March 26, 2004 12:29 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Phone generator/ringer overcomplicated?
If memory serves, a telephone line puts out around a 100 volt AC swing
for a
phone to ring. Can't remember if this is a square wav or sine wave, but
I'm
guessing a square wave would work. A phone does indeed present a
specific
impedance load to the line, around 600 ohms or so. If that's the case
(and
I'm pretty sure it's close) you could hook the output of the stamp to
drive
a little IC audio amplifier with a 12-volt power supply, or even a FET,
remembering the flyback diode. You can probably get the voltage up to
the
needed level with a 10:1 transformer, but you'll have to match the
frequency
of the AC wav, which escapes me at the moment. Should be pretty simple
once
you verify voltage and such.
And yes, you can get a pretty good shock from the phone line when it
rings.
Been there... Done that...
Mike Sokol
mike@f...
www.fitsandstarts.com
" One should not increase, beyond what is necessary,
the number of entities required to explain anything"...
-William of Occam-
Original Message
From: "iphillipsca" <iphillips@s...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, March 26, 2004 11:46 AM
Subject: [noparse][[/noparse]basicstamps] Phone generator/ringer overcomplicated?
> I need to build a phone ringer (I have the frequency generator).
> What is needed is when the operator pushes the buttor the phone
> selected, it rings like a real phone untill the receiver is picked
> up. I was looking at timer relays but they are about as expensive as
> using a stamp and icecube relays. Does this seem right or am I
> overdoing it again with a stamp? Any help appreciated.
> Ian
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject
and
Body of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
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4 seconds pause. Use a dpdt relay, controlled by the 555's, to switch
the ring generator in and out of the loop. Since you apparently have a
pair of wires going to the phone on the remote end. An optocoupler in
series with your loop current, or parrallel if you prefer, will give you
the answer detect. The only hard thing is catching the phone being
picked up DURING a ring. Have the operator switch set a latched relay,
and the loop current detector release the switch. Course, you can by a
phone line simulator for under a hundred bucks that will do all this for
you, including providing loop current to the far end.
iphillipsca wrote:
>
> I need to build a phone ringer (I have the frequency generator).
> What is needed is when the operator pushes the buttor the phone
> selected, it rings like a real phone untill the receiver is picked
> up. I was looking at timer relays but they are about as expensive as
> using a stamp and icecube relays. Does this seem right or am I
> overdoing it again with a stamp? Any help appreciated.
> Ian
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>