8.1. Overview 
The HG 3500 gateway provides IP phones and analog devices access to
the full range of OpenScape 4000 features via CorNet IP.
The HG 3500 provides the following features and benefits:
- Provides the full OpenScape 4000 feature set to the following IP phones:
- optiPoint 4x0 CorNet IP
- OpenStage family,
- AP 1120 analog adapter (For more details please refer to the E-Doku pages in the intranet (http://apps.g-dms.com:8081/edoku/jsp/searchresult_v2.jsp?edokutype=&search_mode=product&product=AP%201120&product_version_main=&product_version_sub=&search_term_type=all&term=&sort_result=title&docclass=&language=&checkdate=&lang=en))
- The HG 3500 line gateway supports direct media connections between IP clients resulting in highest quality voice and minimal delays.
- High voice quality. On account of longer voice signal delays caused by the system in the IP network, voice quality will be impaired by echo unless this is removed prior to transmission. The HG 3500 therefore feature an integrated echo canceller.
- The HG 3500 provides a 10BT/100BT IP network interface and supports up to 240 IP phones off a single gateway.
- Lower bandwidth requirements.
- The HG 3500 supports all phone adapters that do not require their own b channel (not supported are: phone adapter, a/b adapter, S0 adapter, V.24 adapter).
- The HG 3500 supports gateways that protect multiple gateways against failure.
- The HG 3500 supports mobility including support for E911.
- Supports central administration via OpenScape 4000 Management identical to traditional subscribers.
- Support for IP phones provides user mobility and greatly simplified MAC.
- Takes advantage of existing IP infrastructure.
- Supports up to 12,000 IP subscribers off a single OpenScape 4000 including IP users on IP Access Points.
- Support for Quality of Service in the IP network through prioritization.
The HG 3500 supports prioritization in the IP network on the basis of
the following standards:
- IEEE 802.1 p/q (VLAN Tagging) on Layer 2
- IETF RFC 2474 (DiffServ) on the IP Layer
- Support of network management on the basis of SNMP. HG 3500 supports network management on the basis of the SNMP protocol. Statistical data from the applicable standard MIBs and additional data from proprietary MIBs can be queried.