Line Sense Relays

Clare Line Sense Relays address telephony hook switch monitoring and rotary dial pulse counting while addressing regulatory needs. The line sensing relay devices are ideally suited to work the Dial Pulse Counter Hook Switch Monitor Device (M-959) as well as other Tone products offered by Clare such as the M-8870 DTMF Receiver.

M-949-11 Balanced Dual Coil Telephone Line Current Sensing Relay (Data Sheet)

• Senses telephone line current from 15 to 200mA
• Used by control circuitry for on-hook/off-hook monitoring, switch hook flash detection and rotary dial pulse
• Meets high isolation voltage requirement of 4000V
• Meets UL and British Standard specifications
• Includes 1 Form A relay contact

AN-142: M-949 - Loop Current Sensing and Ring Chatter

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M-959 Dial Pulse Counter and Hook Status Monitor (Data Sheet)

• Independent hook status monitoring
• Time-guarded dial pulse counting
• 10 or 20 PPS dialing speeds pin selectable
• Valid data output strobe

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M-949-01 Line Sense Relay (Data Sheet)
(M-949-01 is now obsolete: M-949-11 is Clare's recommended alternative device.)

• Senses telephone line current from 18 to 125 mA
• Used by control circuitry for on-hook/off-hook monitoring, switch hook flash detection and rotary dial pulse
• Provides 1500Vdc coil-to-contact isolation
• Includes 1 Form A relay contact
• Applications Include: central office products, PBX and key systems, rotary dial monitoring devices

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