Telephone Schematic Diagrams

'phone rang' indicator light	Report Broken Link
1-line telephone status indicator (PDF)	Report Broken Link
300 baud modem circuit schematic	Report Broken Link
4-line telephone status indicator (PDF)	Report Broken Link
8-line intercom system using 89C51 microcontroller	Report Broken Link
Assorted telephone circuits	Report Broken Link
Audio Visual Ringer	Report Broken Link
Caller ID decoder	Report Broken Link
Caller ID decoder	Report Broken Link
Cellular Phone calling Detector	Report Broken Link
Conversation Recorder	Report Broken Link
Cordless phone backup	Report Broken Link
Cut Phone Line Detector	Report Broken Link
Cut phone line detector	Report Broken Link
Cut telephone line detector	Report Broken Link
DTMF decoder	Report Broken Link
Detecting a telephone RING	Report Broken Link
Digisound ring modulator	Report Broken Link
Digital/Standard Phone Line Tester	Report Broken Link
E-Lock	Report Broken Link
FM Telephone Bug	Report Broken Link
FM telephone line bug transmitter	Report Broken Link
Greek telecard reader	Report Broken Link
Having secrecy in parallel telephones	Report Broken Link
Hold function for Telephone	Report Broken Link
Home made PBX / PABX	Report Broken Link
Incoming call indicator	Report Broken Link
Infinity Transmitter Schematic and Plans	Report Broken Link
Line in use indicator (PDF)	Report Broken Link
Multipurpose Circuit for telephone	Report Broken Link
NCDS Interface Schematic for Nokia 3110, 8110, 8110i	Report Broken Link
Off line Telephone tester	Report Broken Link
Old phones as an intercom	Report Broken Link
Phone Broadcaster	Report Broken Link
Phone Busy Indicator	Report Broken Link
Phone In-Use Light	Report Broken Link
Phone Intercepter 1	Report Broken Link
Phone Line to Audio	Report Broken Link
Phone Off-Hook Indicator	Report Broken Link
Phone Screener with Voice	Report Broken Link