IDM NTD421（CS）磁石电话光端机

---

title: "IDM NTD421 (CS) Magneto Telephone Optical Terminal"
model: "IDM NTD421"
category: "Telephone Optical Terminal"
tags:

• "Magneto Telephone Optical Terminal"
• "Chain Network Magneto Telephone Optical Terminal"
• "Ring Network Magneto Telephone Optical Terminal"
  description: "Provides 2 telephone channels + 2 groups of physically isolated 100M Ethernet ports, of which ports 1, 2, 3 and the fourth port are physically isolated, with 220V power supply. Dual physically isolated wire-speed 100M Ethernet channels; the 3 shared 100M Ethernet ports can also be divided into VLANs for isolation. The voice interfaces can be FXO central office automatic telephone, FXS remote automatic telephone, or MAG magneto telephone, and provide 2 RS485 interfaces. It can form chain network and ring network applications with dual optical port cascading. The 8-position DIP switch on the panel is used to set the station address in the chain network. Provides a standard SNMP network management interface."
  cover: "/images/imports/img-857c44a0.webp"
  images:
• "/images/imports/img-857c44a0.webp"
• "/images/imports/img-986686c7.webp"
• "/images/imports/img-84b022c1.webp"
  specs:
  "Transmission Distance": "20Km, optional long-distance optical modules are available for extended fiber transmission over longer distances"
  keywords: "Magneto Telephone Optical Terminal,Chain Network Magneto Telephone Optical Terminal,Ring Network Magneto Telephone Optical Terminal"
  slug: "idm-ntd421-cs"
  publishDate: "2026-05-12"

I. Overview

The IDM NTD421 (CS) Magneto Telephone Optical Terminal is a new generation optical-electrical integrated transmission device launched by Beijing Raytrans Digital Technology Co., Ltd., based on high-speed optical fiber transmission technology and PCM technology. It integrates Ethernet transmission and PCM multi-service access functions, meeting the demands of users for fiber transmission and access of various broadband and narrowband services. The IDM NTD421 (CS) Magneto Telephone Optical Terminal can directly connect remote telephones, computers, cameras, and other terminals; when paired with the corresponding G3CP boards, it can support point-to-point, chain network, ring network, and other network topologies. The optical terminal can be widely applied in private networks such as public security, electric power, railway, and mining, as well as public network fields including Mobile, Unicom, and Telecom.

II. Product Features

Ø The optical terminal adopts a desktop chassis structure design with high integration and compact size;

Ø Integrates high-speed optical fiber transmission, PCM service access, and Ethernet access technologies into the device;

Ø Supports 2 channels of 250Mbps optical transmission interfaces with FC optical module interface format, capable of forming chain network, ring network, or point-to-point optical port mutual backup networking;

Ø 4 Ethernet interfaces; in point-to-point mode, every two share 1 physically isolated wire-speed 100M Ethernet; in chain networking mode, the 4 Ethernet ports share one group of wire-speed 100M Ethernet;

Ø The optical terminal provides two magneto telephone channels (MAG);

Ø The optical terminal provides two half-duplex RS485 interfaces, or one full-duplex RS422 interface;

Ø Can form point-to-point, chain network, and other network topologies; the standard model has a non-repeater transmission distance of 40 kilometers; distances beyond this can be customized;

Ø DC5V power supply.

III. Technical Specifications

1) Optical Interface

Interface Type	FC	Fiber Mode	Single-mode (Multi-mode optional)
TX/RX Rate	250M/250M	TX/RX Wavelength	1310nm/1550nm

Optical Output Power	-12~-6dBm	Receiver Sensitivity	Better than-18dBm
Transmission Distance	20Km, with optional long-distance optical modules available for extended fiber transmission over greater distances

2) Ethernet

Interface Type	RJ-45	Transmission Rate	10M/100M/1000M auto-negotiation
Standard Protocol	Supports IEEE802.3	Operating Mode	Full/half-duplex/auto-negotiation

3) FXO, FXS Interfaces

Audio Range	300Hz~3400Hz	Compression	A-law per ITU G.711
Impedance	Three-element complex impedance 200Ω+560Ω//0.1μF	Loop Current	20mA/channel

4) Power Supply and Power Consumption

Power Supply

AC220V/DC-48V

Power Consumption

≤90W

5) Environmental Conditions

Operating Temperature

-10oC ~+50oC

Relative Humidity

0~95% (non-condensing)

6) Product Dimensions

Length×Depth×Height

××(mm)

        IDM NTD421 (CS) Optical Multiplexer Front Panel      IDM NTD421 (CS) Optical Multiplexer Rear Panel