This is the only telephone recording connector that will not cause a hum, buzz or background noise on digital recorders with XLR three prong connections. The Marantz PMD660, PMD661, PMD671 and the PMD661MKII are all compatible with the TP911 Telephone coupler.
The TP911 has its own power supply that grounds the telephone pickup to eliminate buzzing or humming produced by interference and ground loops.
Manufactured and tested to work with all digital products that use a XLR, especially Marantz Professional. Perfect for voice activated recording of phone calls on digital recording units.