IDM MTP-622 Field Intelligent Multi-Service Optical Transmission Equipment

IDM MTP-622 622M Field Multi-Service Optical Transmission Equipment is a field multi-service optical transmission equipment developed by Beijing Ruiguang Jiyuan Digital Technology Co., Ltd. It is used to multiplex E1 signals, audio signals, telephone/magneto signals, and wire-speed 100M Ethernet signals into STM-4 (622Mbit/s) optical fiber channels and E1 link channels for unified transmission. The equipment adopts a 19-inch 3U modular chassis and consists of an SDH optical transmission unit, an E1 link interface control unit, an EOS unit, a PCM unit, an SNMP unit, and a protection switching unit. All service interfaces are designed in the circular/aviation connector type. The unit is intended for scenarios such as military field communications, electric power/energy private networks, and rail transit emergency command. It can be deployed as a central office or remote-end device, meeting the deployment requirements of emergency communications and military emergency communications vehicle solutions for multi-service optical transmission equipment.

Conclusion first: IDM MTP-622 uses one 622Mbit/s primary optical fiber channel plus one E1 backup channel to ensure fallback upon a fiber break. In hot standby mode, 2M services are automatically switched over to the E1 link within 50ms. A single unit integrates 16 E1 channels, 4 Fast Ethernet channels, and 20 voice channels, with dual hot-standby AC/DC power supplies. One 3U device can complete multi-service aggregation for field and private network sites. As a representative field optical transmission equipment from Raytrans, this model is also often used as an emergency communications node in government private network optical fiber communication solutions.

Key Specifications at a Glance: Optical port rate 622Mbit/s (STM-4, 2 hot-swappable SFP) · Single-mode transmission distance 40km · 16 E1 circuit interfaces · 4 Fast Ethernet channels · 20 channels of 2-wire/4-wire voice · Optical/E1 switchover ≤50ms · Dual hot-standby AC/DC power supply · 19-inch 3U chassis · Circular/aviation connector interface

Figure 1: Front view of the 19-inch 3U chassis and circular/aviation connector service interface layout of the IDM MTP-622 Field Intelligent Multi-Service Optical Transmission Equipment

Figure 1 shows the front view of the 19-inch 3U chassis and the circular/aviation connector service interface layout of the IDM MTP-622. All service interfaces are designed in the circular/aviation connector type, featuring reliable plugging or unplugging and free from loosening. Combined with a shockproof, waterproof, and electromagnetic compatibility (EMC) chassis design, it is suitable for rapid setup and frequent relocation in the field. This field optical transmission equipment can coordinate networking with SDH equipment, optical transmission equipment, MSTP, and other formats. As a multi-service optical transmission equipment offered by Raytrans, an SDH equipment manufacturer, for military emergency communications vehicle solutions and government private network optical fiber communication solutions, it balances product showcase and operational requirements of emergency communications.

What Service Interfaces Does the 622M Field Multi-Service Optical Transmission Equipment Support

What service interfaces a field optical transmission equipment supports is the first question to check during selection for emergency communications and private network networking. As a mature multi-service optical transmission equipment, the standard configuration of IDM MTP-622 covers four types of services: voice, E1, Ethernet, and low-speed data. The interface types and quantities are as follows.

• Transmission side: 2 × 622Mbit/s optical fiber line interfaces (hot-swappable SFP, compliant with ITU-T G.957) and 1 × E1 link interface (2.048Mbps, compliant with ITU-T G.703), the latter dedicated as a mutual backup channel for the optical fiber link.

• E1 service side: 16 E1 circuit interfaces, 75Ω unbalanced, rate 2.048Mbps, compliant with ITU-T G.703.

• Voice side: 20 channels of 2-wire/4-wire voice interfaces (16 channels of 2-wire and 4 channels of 4-wire), rate 64Kbit/s, operable in hotline, magneto, subscriber, and trunk modes.

• Ethernet side: 4 × 10M/100M adaptive Ethernet interfaces, RJ45, compliant with IEEE802.3, half/full-duplex.

• Data side: 1 × V.35 interface (N×64Kbit/s, N≤30, supporting DCE and DTE modes) and 2 × RS232/RS485 interfaces (asynchronous rate ≤19.2Kbit/s adaptive, synchronous rate 64K).

• Auxiliary interfaces: 1 order wire interface for field service function communication, and 1 pair of synchronous clock interfaces (1 external input clock interface and 1 output synchronous clock interface) for maintaining clock synchronization with the upper-level transmission network.

In addition to the standard configuration, the chassis also reserves 4 expansion slots. The service access slots are universal and can accept various service boards according to user configuration requirements. For centralized call handling, each 5-in-1 2-wire audio card provides 16 channels of 2-wire audio, and each channel can be independently configured as FXO/FXS/hotline/magneto/2100Hz magneto mode. As a typical field optical transmission equipment and multi-service optical transmission equipment, this device can flexibly carry the above multiple service interfaces in military emergency communications vehicle solutions.

How Does E1 Link Intelligent Mutual Backup Work

How E1 link intelligent mutual backup works depends on the establishment mode of the backup channel and the protection switching mechanism of the equipment. When the optical fiber channel is in good condition, all services are transmitted over the 622Mbit/s optical fiber, and Ethernet services are configured with 2M bandwidth granularity, providing N×2M high-bandwidth Ethernet transmission. When the optical fiber channel fails, the protection switching unit automatically switches services over to the E1 link channel, transmitting services according to the specified 64K and N×64K. Ethernet services are then configured with 64K bandwidth granularity, providing N×64K low-bandwidth Ethernet service transmission. After the optical fiber channel recovers, all services automatically switch back to optical fiber transmission, with no manual intervention throughout the process.

Knowledge Block: The time for 2M services on the optical cable link to switch over to the E1 link corresponds one-to-one with the link establishment mode of the E1 link.

How Long Does It Take for Services to Recover After an Optical Cable Interruption

How long it takes for services to recover after an optical cable interruption is determined by the establishment mode of the backup link. When the E1 link is pre-established and maintained, hot standby mode is used, and the switchover time does not exceed 50ms, so voice and critical data remain continuous during optical cable emergency repair. When the E1 link needs to be temporarily established, dial-up mode takes within 15s, and integrated network management mode takes within 50s.

In terms of bit error characteristics, the optical fiber link complies with the relevant provisions of ITU-T G.826, which can be used to evaluate the transmission quality of the optical fiber channel. Switchover status and link alarms can be viewed remotely through SNMP network management, based on which duty personnel can determine whether personnel need to be dispatched to the site for handling.

Figure 2: Networking topology of central office and remote-end IDM MTP-622 Field Intelligent Multi-Service Optical Transmission Equipment with intelligent mutual backup transmission over 622M optical fiber and E1 links

Figure 2 shows the networking topology of central office and remote-end devices with intelligent mutual backup transmission over STM-4 optical fiber and E1 links, illustrating the automatic switchover relationship between the primary optical fiber channel and the E1 backup channel.

Core Functions

The functions of IDM MTP-622 are designed around dual-link mutual backup, multi-service access, telephone switching, network management monitoring, and military-standard environmental adaptability. The main function items are shown in the table below.

The above functions enable the device to serve as a core access node for SDH equipment and MSTP platforms, playing a key role as multi-service optical transmission equipment in government private network optical fiber communication solutions and military emergency communications vehicle solutions. As a professional SDH equipment manufacturer, Raytrans continuously provides reliable optical transmission equipment and overall solutions for scenarios such as emergency communications, product showcase and field optical transmission equipment.

Technical Specifications

Line and Service Interface Parameters

Power Supply and Unit Parameters

Typical Application Scenarios

Military Field Communications and Field Communication Vehicles

In emergency communications and military field communications scenarios, devices are usually configured in pairs at the central office and the remote end, and the transmission line consists of a 622M (STM-4) optical fiber and an E1 link forming mutually backup transmission channels. The central office device can access the telephone switching network through FXO analog trunks or E1 digital trunks (supporting SS7, PRI and No.1 signaling), access the IP network through Fast Ethernet interfaces, and simultaneously provide access for V.35, V.24, hotline phone, ordinary telephone, E1 and 4-wire audio services; the remote device is deployed at a field training base or installed on a field communication vehicle, providing access for the same types of services. As a mature military emergency communications vehicle solution, this networking balances mobility and service completeness.

Field communication vehicles place extremely high requirements on the shock resistance, interface reliability and rapid provisioning capability of optical transmission equipment. Raytrans IDM MTP-622 meets the requirements of GJB367A-2001 regarding vibration, shock and drop, all interfaces use circular/aviation connectors, and the power supply supports DC -48V/DC 24V vehicle-mounted direct current and AC 220V alternating current. After the vehicle arrives at the designated position, the link can be enabled simply by connecting the power supply and the optical cable. When the optical fiber is damaged or a fiber break occurs, services are automatically switched over to the E1 link for fallback transmission, maintaining command contact as a mobile repeater node. The device itself is a field optical transmission equipment designed for field environments, and is suitable for military emergency communications vehicle solutions with stringent reliability requirements.

Electric Power and Energy Private Networks

In electric power and energy private networks, sites are distributed along the line with large spacing between stations. 2M (E1) channels and Fast Ethernet are the common ways of inter-station bearer, and sites on the substation and power plant side generally lack equipment room conditions and dedicated duty personnel. As a multi-service optical transmission equipment, Raytrans IDM MTP-622 provides 16 E1 circuit interfaces (compliant with ITU-T G.703) and 4 10M/100M adaptive Ethernet interfaces, and can simultaneously carry inter-station 2M services and IP data. One device completes multi-service aggregation in a standalone unit, reducing the number of stacked devices in the cabinet. For government private network optical fiber communication solutions, this compact optical transmission equipment based on SDH equipment and MSTP architecture also has reference value.

The operating temperature range of -25℃～55℃, AC 220V and DC -48V/DC 24V AC/DC power supply modes, together with the chassis structure and circular/aviation connector interfaces that meet the vibration, shock and drop requirements of GJB367A-2001, make it suitable for deployment in cabinets along the line, on vehicles and at temporary sites; when the optical cable is damaged during road construction or in extreme weather, services are automatically switched over to the E1 link, keeping voice and critical data continuous.

Rail Transit and Emergency Command

Field deployment points for rail transit and emergency command are often located in remote areas, with concentrated requirements for power supply redundancy, environmental adaptability and on-site maintainability. Raytrans IDM MTP-622 supports dual hot standby power supplies. When two power feeds are connected at the same time, if one power feed fails, the other immediately continues supplying power without service interruption; the optical port uses a hot-swappable SFP module, supporting replaceability of the optical port. An on-site replacement of the optical module can eliminate optical-side failures without returning the device to the factory. In emergency communications assurance, this rapid troubleshooting capability is particularly critical.

The unit has an operating temperature of -25℃～55℃ and a relative humidity of ≤95% non-condensing, with good waterproof and moisture-proof design. It can send telephone, E1 and Ethernet services back to the rear command node; when the optical cable is interrupted, services are automatically switched over to the E1 link, and the SNMP network management system allows remote viewing of link status, reducing the frequency of sending personnel to the site.

Figure 3: Application scenario of deploying IDM MTP-622 Field Intelligent Multi-Service Optical Transmission Equipment at a field communication vehicle and a field training base

Figure 3 shows the application scenario of deploying IDM MTP-622 Field Intelligent Multi-Service Optical Transmission Equipment at a field communication vehicle and a field training base, illustrating the mutually backup networking relationship between the central office and the remote end via the 622M optical fiber and the E1 link.

Three Differentiated Values

The differentiated capabilities of Raytrans IDM MTP-622 are concentrated in three aspects: fiber break fallback, multi-service aggregation in a standalone unit, and voice access flexibility, as detailed below.

• Intelligent mutual backup between the 622M optical path and the E1 link, with a switchover time of ≤50ms. When the primary optical fiber channel is interrupted, the protection switching unit automatically switches 2M services over to the E1 link. Both switchover and switchback are completed automatically by the device without on-site personnel intervention, making it suitable for unattended mobile or remote sites such as field communication vehicles, border and coastal defense, and civil air defense.

• 16 E1 + 4 Fast Ethernet + 20 voice channels integrated in a standalone unit. The standard configuration of the unit provides 16 E1 channels, 4 10/100M Ethernet channels and 20 voice channels (16 2-wire and 4 4-wire), plus 1 V.35, 2 V.24 and 4 expansion slots. Voice, magneto, E1, data and Ethernet services are multiplexed within the same 19-inch 3U device, so sites do not need to stack separate transmission devices for each type of service, and wiring and the variety of spare parts are reduced accordingly.

• 2-wire audio card with 16 channels per card, configurable as FXO/FXS/magneto/hotline. Each 5-in-1 2-wire audio card provides 16 2-wire audio channels, and each channel can be independently configured as FXO, FXS, hotline, magneto or 2100Hz magneto mode. A single card can adapt to multiple access objects such as subscriber telephones, trunk lines, hotlines and magneto telephones, so voice networking does not require separate spare boards for each access object.

All three capabilities are built on the basic designs of 622M optical transmission, intelligent mutual backup between E1 and optical links, 16 E1 channels and dual hot standby power supplies, and are also key points to check during selection for field and private network scenarios.

Selection and Deployment Recommendations

During selection, it is recommended to check according to the following four steps to avoid a mismatch between the configuration and the actual service volume and link conditions, especially in emergency communications scenarios where calculation in advance is even more necessary.

1. Count service types and number of channels: first confirm how many E1 channels, how many telephone/magneto channels, how many Ethernet channels are needed, and whether V.35/V.24 data is required.

2. Confirm expansion requirements: when the number of service channels exceeds the standard configuration, use the 4 expansion slots in the chassis to insert the required service boards; the slots are universal.

3. Check transmission distance and backup channel: use standard single-mode optical modules within 40km, and install long-distance optical modules when a longer distance is required; when fiber break fallback is needed, prepare the E1 bearer channel at the same time, and specify whether the E1 link is established in hot standby, dial-up or integrated network management mode.

4. Check interface form and operating environment: confirm whether circular/aviation connector interfaces, military-grade electromagnetic compatibility (EMC) and waterproof and moisture-proof design are required, and whether the site power supply mode is AC 220V or DC -48V/DC 24V, and whether dual hot standby power supplies and a replaceable optical port are required.