Siemens Gigaset A580IP (Additional Handsets A58H) Multiline flexibility: register up to 6 handsets and use up to 6 SIP accounts from multiple providers Internet and fixed line calls – up to 3 in parallel Exceptional sound with High Definition Sound Performance™ ¹ Worldwide free calling between Gigaset IP phones via Gigaset.net ¹ Online net directory and Yellow Page Search Illuminated B/W display (3 lines + 1 line for soft keys) Codecs: G.711,G.722, G.726, G.729AB Range: Indoor/Outdoor - 50 m | 300 m Standby time/Talk time - 210 h | 25 h Additional handsets model A58H are available. Please see link below for all A580IP information-: http://gigaset.com/shc/0,1935,hq_en_0_160891_rArNrNrNrN,00.html