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
Yealink T54W IP Phone, 16 VoIP Accounts. 4.3-Inch Color Display - Black
$99.99
LOT OF 10 Cisco CP-7841-K9 VoIP 4-Line Business Phone w/ Stand Handset Cord
$69.99
Yealink SIP-T41P PoE Ultra Elegant VoIP Phone
$29.95
Yealink W73H IP DECT VOIP Phone
$10.00
Polycom VVX 411 Business IP Phone 12-Line Gigabit PoE VOIP 2200-48450-001 NEW
$48.00
New Cisco 7945G IP VoIP Gigabit GIGE Telephone Phone CP-7945G -
$24.95
Cisco CP-7945G VOIP Phone With Stand & Handset Business IP Phone 7945
$3.00
NEW Open Box Polycom CCX 400 VoIP Desk Phone PoE 2200-49700-001 (BR)
$107.96
Cisco CP-8821-K9 Wireless IP VoIP Phone WITH BATTERY
$199.99