Protocols/standards
SIP RFC3261, TCP/IP/UDP, RTP/RTCP, RTCP-XR, HTTP/HTTPS, ARP, ICMP, DNS
(record, SRV, NAPTR), DHCP, PPPoE, SSH, TFTP, NTP, STUN, SIMPLE, LLDP, LDAP,
TR-069, SNMP, 802.1x, TLS, SRTP, IPv6
Network interfaces
Two 10/100 Mbps switched Ethernet ports with automatic
detection, built-in PoE power supply (GRP2601P model only)
Wi-Fi
GRP2601W, single frequency, 2.4GHz, 802.11 b/g/n/ax (2.4G only)
Graphic display
LCD display with a resolution of 132 x 48 (2.41 inches)
Function buttons
Four programmable context-sensitive XML on-screen keys, five keys
(navigation, menu). Eight special function keys: MESSAGE
(with LED indicator), TRANSMISSION, HEADSET, MUTE,
sending/REDIAL, LOUD FREEDOM MODE, VOLUME+,
VOLUME
Codecs and voice functions
Support G.729A/B, G.711µ/a-law, G.726, G.722 (Broadband), G.723, iLBC, OPUS,
DTMF in-band and out-of-band (audio input, RFC2833, SIP INFO), VAD, AEC, CNG,
PLC, AGC, AYB
Phone Functions
Hold, redirect, transfer, five-way conference,
parking calls, answering calls, ph