Accordingly to the following Technical Specification these protocols are supported on the VG224 including HSRP:-

PROTOCOLS SUPPORTED

• SCCP

• H.323v4

• MGCP

• SIP

• Real-Time Transport Protocol (RTP)

• Secure Real-Time Transport Protocol (SRTP)

• Trivial File Transfer Protocol (TFTP)

• HTTP server

• SNMP

• Telnet

• Dynamic Host Configuration Protocol (DHCP)

• Domain Name System (DNS)

• Cisco Unified CallManager 3.3.3 SR2 or higher version

• Cisco Unified CallManager Express 4.3.2 or higher version

• Cisco Unified CallManager or Cisco Unified CallManager Express redundancy support using Hot Standby Router Protocol (HSRP)

• Call survivability-MGCP failover to an H.323 connection to the SRST router

• Cisco fax relay, T.38 fax relay, and modem pass-through

• Coder/decoder (codec) support, G.711, G.729a

• RADIUS and TACACS+ for Telnet and authorization

Refer to the following URL:-

http://www.cisco.com/en/US/prod/collateral/voicesw/ps6790/gatecont/ps2250/ps5516/product_data_sheet09186a00801d87f6.html

Rgds

Allan.