General Knoppix support for those who've read the FAQ at the Wiki
Cisco CP-7841 4-Line VoIP Phone
$62.99
Cisco CP-8811 VoIP Phone 5-Line 5" LCD Display (Gray)
$55.50
Polycom VVX 450 Ring Central Business VoIP Phone Black
$59.91
Cisco CP-8821-K9 Wireless IP VoIP Phone WITH BATTERY
$99.99
Grandstream GS-HT802 2 Port Analog Telephone Adapter VoIP Phone & Device, Black
$32.00
Cisco CP-7945G VOIP Phone With Stand & Handset Business IP Phone 7945
$3.00
Lightly Used Cisco 8811 Series VoIP phone Factory Reset great condition
$19.95
Cisco/Linksys SPA2102 VoIP Phone Adapter Router 2FXS (Unlocked)
$16.99
Cisco 8841 CP-8841-K9 VoIP Business IP Phone (Charcoal)
$45.00
Yealink T54W IP Phone, 16 VoIP Accounts. 4.3-Inch Color Display - Black
$99.99