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		<title><![CDATA[Circuit Finder - Telephone related]]></title>
		<link>http://www.circuit-finder.com/categoriestelephone-related/page-1</link>
		<description><![CDATA[ ]]></description>
		<language>en</language>
		<copyright><![CDATA[Copyright © 2026., Circuit Finder - circuit diagrams database ]]></copyright>
		<webMaster>jokam85@gmail.com(Site Admin)</webMaster>
		<pubDate>Fri, 06 Mar 2026 12:53:20 +0000</pubDate>
		<lastBuildDate>Fri, 06 Mar 2026 12:53:20 +0000</lastBuildDate>
		<category><![CDATA[Telephone related]]></category>	
		<docs>http://blogs.law.harvard.edu/tech/rss</docs>
		<ttl>60</ttl>
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			<guid>http://www.circuit-finder.com/categories/telephone-related/intercom/137/high-quality-intercom</guid>
			<title><![CDATA[High Quality Intercom]]></title>
			<link>http://www.circuit-finder.com/categories/telephone-related/intercom/137/high-quality-intercom</link>
			<description><![CDATA[A very high quality intercom, which may also be used for room monitoring.]]></description>
			<category>Intercom</category>
			<pubDate>Sat, 25 Dec 2010 14:29:21 +0000</pubDate>
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		<item>
			<guid>http://www.circuit-finder.com/categories/telephone-related/intercom/150/intercommunication-intercom</guid>
			<title><![CDATA[Intercommunication (Intercom)]]></title>
			<link>http://www.circuit-finder.com/categories/telephone-related/intercom/150/intercommunication-intercom</link>
			<description><![CDATA[This is a great intercom circuit that can be used in many ways. It uses 22V to operate and maybe it will work at a lower voltage (you can try it). For input/output it uses a loundspeaker (20-45 Ohm) on each side.]]></description>
			<category>Intercom</category>
			<pubDate>Wed, 08 Dec 2010 13:06:16 +0000</pubDate>
		</item>
				
				
		<item>
			<guid>http://www.circuit-finder.com/categories/telephone-related/miscellaneous-telephone/256/phone-hold-with-music</guid>
			<title><![CDATA[Phone &quot;Hold&quot; With Music]]></title>
			<link>http://www.circuit-finder.com/categories/telephone-related/miscellaneous-telephone/256/phone-hold-with-music</link>
			<description><![CDATA[This circuit will allow you to place a phone call on hold and if you wish to have them listen to music while they are on hold.]]></description>
			<category>Miscellaneous telephone</category>
			<pubDate>Thu, 02 Dec 2010 12:07:24 +0000</pubDate>
		</item>
				
				
		<item>
			<guid>http://www.circuit-finder.com/categories/telephone-related/line-monitor/257/phone-busy-indicator</guid>
			<title><![CDATA[Phone Busy Indicator]]></title>
			<link>http://www.circuit-finder.com/categories/telephone-related/line-monitor/257/phone-busy-indicator</link>
			<description><![CDATA[Have you ever been using the modem or fax and someone else picks up the phone, breaking the connection? Well, this simple circuit should put an end to that. It signals that the phone is in use by lighting a red LED. When the phone is not in use, a green LED is lit. It needs no external power and can be connected anywhere on the phone line, even mounted inside the phone.]]></description>
			<category>Line monitor</category>
			<pubDate>Thu, 02 Dec 2010 12:03:52 +0000</pubDate>
		</item>
				
				
		<item>
			<guid>http://www.circuit-finder.com/categories/telephone-related/miscellaneous-telephone/394/soft-musical-telephone-ringer</guid>
			<title><![CDATA[Soft Musical Telephone Ringer]]></title>
			<link>http://www.circuit-finder.com/categories/telephone-related/miscellaneous-telephone/394/soft-musical-telephone-ringer</link>
			<description><![CDATA[The normal telephone bell, at times (specially during night when one does not want to be disturbed), appears to be quite irritating. The circuit shown here converts the loud sounding bell into a soft and pleasing musical tone.]]></description>
			<category>Miscellaneous telephone</category>
			<pubDate>Tue, 30 Nov 2010 14:17:05 +0000</pubDate>
		</item>
				
				
		<item>
			<guid>http://www.circuit-finder.com/categories/telephone-related/miscellaneous-telephone/316/ringing-phone-light-flasher</guid>
			<title><![CDATA[Ringing Phone Light Flasher]]></title>
			<link>http://www.circuit-finder.com/categories/telephone-related/miscellaneous-telephone/316/ringing-phone-light-flasher</link>
			<description><![CDATA[You are asking how to connect up some lights so that when the phone rings, they flash. This is very useful in a situation were there is lots of noise and it is impossable to hear the phone, such as a workshop. Here is such a device. The ring detect part of this circuit came from]]></description>
			<category>Miscellaneous telephone</category>
			<pubDate>Tue, 30 Nov 2010 14:08:00 +0000</pubDate>
		</item>
				
				
		<item>
			<guid>http://www.circuit-finder.com/categories/telephone-related/miscellaneous-telephone/72/cellular-phone-calling-detector</guid>
			<title><![CDATA[Cellular Phone calling Detector]]></title>
			<link>http://www.circuit-finder.com/categories/telephone-related/miscellaneous-telephone/72/cellular-phone-calling-detector</link>
			<description><![CDATA[This circuit was designed to detect when a call is incoming in a cellular phone (even when the calling tone of the device is switched-off) by means of a flashing LED.]]></description>
			<category>Miscellaneous telephone</category>
			<pubDate>Mon, 15 Nov 2010 13:19:26 +0000</pubDate>
		</item>
				
				
		<item>
			<guid>http://www.circuit-finder.com/categories/telephone-related/telephone-bug/121/fm-telephone-bug</guid>
			<title><![CDATA[FM Telephone Bug]]></title>
			<link>http://www.circuit-finder.com/categories/telephone-related/telephone-bug/121/fm-telephone-bug</link>
			<description><![CDATA[Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio.]]></description>
			<category>Telephone bug</category>
			<pubDate>Thu, 11 Nov 2010 12:17:39 +0000</pubDate>
		</item>
				
				
		<item>
			<guid>http://www.circuit-finder.com/categories/telephone-related/miscellaneous-telephone/410/telephone-amplifier</guid>
			<title><![CDATA[Telephone amplifier]]></title>
			<link>http://www.circuit-finder.com/categories/telephone-related/miscellaneous-telephone/410/telephone-amplifier</link>
			<description><![CDATA[While talking to a distant subscriber on telephone, quite often we feel frustrated when the voice of the distant subscriber is so faint that it is barely intelligible. To overcome the problem, circuit of an inexpensive amplifier is presented here. It can be assembled and tested easily. There is no extra power source needed to power up the circuit, as it draws power from the telephone line itself. The amplifier will provide fairly good volume for the telephone conversation to be properly heard in a living room. A volume control is included to adjust the volume as desired.]]></description>
			<category>Miscellaneous telephone</category>
			<pubDate>Tue, 09 Nov 2010 15:02:01 +0000</pubDate>
		</item>
				
				
		<item>
			<guid>http://www.circuit-finder.com/categories/telephone-related/line-monitor/413/telephone-line-monitor</guid>
			<title><![CDATA[Telephone line monitor]]></title>
			<link>http://www.circuit-finder.com/categories/telephone-related/line-monitor/413/telephone-line-monitor</link>
			<description><![CDATA[This nifty little circuit lets you record your phone conversations automatically. The device connects to the phone line, your tape recorder's microphone input, and the recorder's remote control jack. It senses the voltage in the phone line and begins recording when the line drops to 5 volts or less.]]></description>
			<category>Line monitor</category>
			<pubDate>Mon, 25 Oct 2010 23:03:54 +0000</pubDate>
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