Telephone and Ethernet Access Application Solution in Tunnels

1、 Requirements

There are 15 chain-type branch access points distributed in a tunnel. Each point requires 2 telephone access lines and 2 groups of physically isolated Ethernet access. The distance between branch nodes is about 2 km. At the central end, aggregation of 30 telephone services and Ethernet services is required.

2、 Network Topology Diagram

Based on this requirement, the central office is configured with IDM-MP200-30EN; the remote end is configured with IDM-NTD421 devices.

At the central end, the IDM-MP200-30EN device is configured with 30 telephone channels, connected to the PBX program-controlled switch. The 2 groups of Ethernet ports are connected to the office network switch and the surveillance network switch respectively.

The IDM-NTD421 device provides 1 or 2 office telephones per node based on the service volume at each node. The office network and surveillance network are connected to the first Ethernet group and the second Ethernet group respectively.

Note: The IDM-NTD421 device has a total of 4 Ethernet ports, which can be divided into 2+2 isolation mode or 1+3 isolation mode, customized before delivery.

The network topology diagram is as follows:

3、Device Introduction

IDM-NT421****Optical Terminal extends data services to various user areas, serving as a substitute for remote small offices, enabling cross-boundary line provisioning, and relieving the switching office; or in urban areas, it solves the constraints of twisted pair in terms of bandwidth and transmission distance, expanding the service coverage of the switching office. This device can be widely applied in telecommunications data services, electric power, banking, public security, military, schools, highways, and other departments for public telephone network access and dedicated line information transmission.

Product Features:

u Single optical port, optical line transmission rate of 250Mbps;

u 4 Ethernet interfaces, each pair sharing 1 physically isolated 100M line-speed Ethernet;

u Provides 2 central office telephone interfaces FXO, or 2 remote telephone interfaces FXS, or magneto telephone MAG;

u Provides 2 half-duplex RS485 interfaces, or 1 full-duplex RS422 interface;

u Can form point-to-point, chain network, and other topologies.

4、Device Selection Table

Product Name	Product Model	Product Description
Dual-Channel Optical Multiplexer	IDM-NTD421	Provides 2 optical ports, 2 telephone channels, and 2 Ethernet groups;
30E-MP	IDM-30E-MP	Provides 2 optical ports, 30 telephone channels, and 2 Ethernet groups; powered by AC220V