Plantronics APN-91 Savi and CS500 series Electronic Hook switch (EHS) cable for NEC DT series phones, including NEC DSX 34B BL, DSX 34B FDX, DTR Series (DTR 8, DTR 8D, DTR 16D, DTR 16LD, DTR 32D) , DTH Series (DTH 8, DTH 8D, DTH 16D, DTH 16LD, DTH 32D), DTL series (DTL 12D, DTL 24D, DTL 8LD, DTL 32D), DT 330, DT 730 and DT 750  compatible with the following Plantronics wireless headsets:

Old Poly part # 89280-11

New HP part # 85Q59AA

Plantronics CS540, CS510, CS520 , Plantronics Savi WO100, Plantronics Savi WO200, Plantronics Savi WO300 Plantronics Savi WO350 , Plantronics Savi W740, Plantronics Savi W710 , Plantronics Savi W720 , Plantronics Savi W730 , Plantronics Savi W745

Also see Plantronics APN-91 datasheet

Important note: Installation of this Plantronics APN-91 cable require a NEC phone technician.  Programming of the NEC phone switch is required.  It cannot be done from the NEC phone, We recommend the  Plantronics HL10 Lifter if a NEC technician is not available

note: There are 2 versions of the NEC DT Series phones - the standard SIP (used with NEC product SIP@NET and 3C) and the i-SIP/N-SIP versions which are used with the SV8100, SV8300 and SV8500. This Plantronics APN-91 cable only works with the i-SIP/N-SIP versions of the DT700 terminals.

Not compatible with NEC DT710

On the Plantronics wireless headset base, use these settings for best results. NEC switch must also be configured for this EHS to work, it cannot be done from the phone menu. See NEC APN-91 release notes for NEC phone setup or contact NEC phone support 1-877-463-2267

Enlarge the picture below for setup instructions: