Have you tried security oriented distro Operator.iso by ussysadmin.org? It is based on knoppix and debian. Also it is one of the best network testing and pen testers tool?
Grandstream GS-HT802 2 Port Analog Telephone Adapter VoIP Phone & Device, Black
$32.00
Fanvil V64 VOIP Business Phone- Black *NEW*
$89.99
Polycom VVX 411 IP VOIP POE Gigabit Telephone [L/N] BUSINESS OFFICE RECEPTION
$24.00
Lot Of 8 Cisco CP-7945G VOIP Business IP Phone w/ Stand and Handset #0358
$162.98
Cisco CP-7945G VOIP Phone With Stand & Handset Business IP Phone 7945
$3.00
Cisco CP-8861-K9 5-Line VoIP Business Phone w/ Stand & Handset
$24.98
Cisco/Linksys SPA2102 VoIP Phone Adapter Router 2FXS (Unlocked)
$16.99
Lightly Used Cisco 8811 Series VoIP phone Factory Reset great condition
$19.95
Grandstream GS-GXP2170 VoIP Phone & Device 4.3" Color-Screen LCD Gigabit Ports
$45.53
Cisco CP-7841 4-Line VoIP Phone
$62.99