IDM 300GP Telephone Optical Multiplexer
Dual physically isolated gigabit, 8 E1 transparent transmission, 30 telephone channels per card, 300 channels in full configuration
The IDM-300GP multi-service optical multiplexer provides 2 physically isolated line-rate 1000M Ethernet interfaces, 8 E1 transparent transmission interfaces, and FXO/FXS interfaces with caller ID. The IDM-300GP multi-service optical multiplexer simplifies transmission lines while reducing costs. The device features a card-based structural design, with each service card providing 30 telephone channels. It is simple to install and easy to maintain.
The IDM 300GP telephone optical multiplexer is a dual-gigabit 8E1 telephone optical multiplexer developed by the optical multiplexer manufacturer Beijing Ruiguang Jiyuan Digital Technology Co., Ltd. It multiplexes 2 physically isolated line-rate 1000M Ethernet interfaces, 8 groups of E1 transparent transmission interfaces, and FXO/FXS voice channels with caller ID (CID) onto a single 2.5Gbps optical fiber channel for transmission. It is a typical multi-service optical multiplexer product for multi-service access scenarios.
The device adopts a card-based structure. A single service card carries 30 channels of 64K telephone audio service, and service cards are inserted according to site traffic. In full configuration, it can provide access to 300 user voice channels. Narrowband voice, E1 trunk, and broadband data each occupy an independent channel over the same optical path. At the site side, one device can complete centralized backhaul of voice and data services, converging both transmission line and rack space occupancy. This product showcases Raytrans's product design capabilities in the telephone optical multiplexer and PDH optical multiplexer fields, and is also suitable for scenarios such as government private network optical fiber communication solutions and military emergency communications vehicle solutions that require integrated voice and data access. Its gigabit network optical multiplexer capability and multi-service optical multiplexer architecture enable a single optical multiplexer to handle backhaul of multiple service types.
Key Specifications at a Glance: 2 isolated gigabit Ethernet interfaces · 8 groups of E1 transparent transmission · 2.5Gbps single-fiber 20Km · 30 telephone channels per card, 300 channels in full configuration · 14 card slots, hot-swappable · AC220V/DC-48V power supply · overall power consumption ≤90W
What kind of equipment is the dual-gigabit 8E1 telephone optical multiplexer
As a card-based telephone optical multiplexer, the IDM 300GP telephone optical multiplexer adopts a centralized card-based chassis structure. The chassis provides 14 card slots: 10 service card slots carry telephone services, 2 main control card slots handle access management for the chassis and service cards, and 2 power card slots provide 1+1 mutual backup power supply. Each service card provides access to 30 channels of 64K telephone audio service. When all 10 service cards are installed, the full configuration of 300 user voice channels is reached, with the number of card slots corresponding one-to-one to voice channel capacity. In Raytrans's product showcase, this product is positioned as a multi-service access platform for private network users.
The unit is a 19-inch standard 6U chassis with dimensions of 482×266×270mm, compliant with telecom and carrier standards, and occupies 6U of installation space in a standard cabinet. All card slots support hot-swappable operation. During commissioning, cards are inserted one by one according to the service list; during O&M, faulty card slots are located by alarm and replaced online without powering down the entire unit. The card-based structure enables installation actions to be positioned by card and capacity expansion actions to be performed by card insertion, making the equipment simple to install and easy to maintain. As an optical multiplexer manufacturer, Raytrans has maintained the unified chassis design of its card-based product line in this model.
Figure 1: IDM 300GP telephone optical multiplexer 19-inch 6U front view with 14 card slots, power supply, and alarm indicator LEDs
What services can one device carry
The IDM 300GP telephone optical multiplexer consolidates telephone, E1, and Ethernet services into the same chassis. It can also be configured with narrowband data interfaces such as codirectional 64K, EM2/4-wire, V.24, and V.35, selected according to the project service list. The table below lists each function and capability description item by item, so that on-site configuration verification can be performed row by row.
| Function | Description |
|---|---|
| 2 physically isolated line-rate gigabit | Provides 2 RJ-45 gigabit Ethernet interfaces, adaptive 10M/100M/1000M, fully isolated at the physical layer, so that service network and surveillance network do not affect each other |
| 8 groups of E1 transparent transmission | Provides 8 groups of E1 transparent transmission interfaces, 4 groups of 75 Ω unbalanced and 4 groups of 120 Ω balanced, selected according to the peer interface type; the original frame structure and service content are transparently transmitted without rewriting |
| 30 telephone channels per card | Each service card provides access to 30 channels of 64K telephone audio service; 10 service cards in full configuration provide 300 user voice channels |
| Caller ID FXO/FXS | FXO and FXS interfaces support caller ID (CID) and can directly connect to analog telephones, fax machines, and switching equipment |
| 2.5Gbps optical transmission channel | Optical line rate 2.5Gbps, SFP optical interface, 20Km over single-mode fiber, extendable with long-distance optical modules |
| Card-based hot-swappable expansion | All 14 card slots support hot-swappable operation; voice channels are expanded by inserting service cards in steps of 30 channels, with the chassis, backplane, and main control card configuration unchanged |
| 1+1 mutual backup power supply | 2 power cards back each other up; if one power card fails, the other continues to supply power to the chassis |
| 6U centralized chassis | 19-inch standard 6U chassis, dimensions 482×266×270mm, compliant with telecom and carrier standards, maintained by card slot positioning |
From the perspective of a multi-service optical multiplexer, this model provides both gigabit network optical multiplexer-level Ethernet carrying capability and PDH optical multiplexer-level E1 transparent transmission capability within the same chassis, with telephone services overlaid in a card-based manner. It is suitable for sites with many service types and capacity that needs to be configured in steps.
How 2 isolated gigabit interfaces and 8 groups of E1 share one optical fiber with telephones
The 2 gigabit Ethernet interfaces are fully isolated at the physical layer, which is the main service-carrying feature of the IDM 300GP telephone optical multiplexer. The two Ethernet interfaces each occupy an independent channel. When one carries dispatch service data and the other carries video surveillance backhaul, there is no packet-level interworking path between the two networks, and the network boundary does not rely on VLAN partitioning or VPN encapsulation. This characteristic allows it to serve as an isolated access node for the service network and surveillance network in government private network optical fiber communication solutions, and also makes it suitable for military emergency communications vehicle solutions with explicit requirements for multi-network isolation.
There are 8 E1 channels in total, of which 4 are 75 Ω unbalanced and 4 are 120 Ω balanced, selected according to the peer equipment interface type. The E1 bit rate is 2.048Mbps, the line code is HDB3, the frame structure is PCM30/32, and channel-associated signaling (CAS) is used. It complies with the ITU-T G.703 standard and operates in transparent transmission mode, allowing direct connection to existing PCM and SDH equipment.
The path by which telephone voice enters the device is as follows: the exchange side accesses via FXO interfaces, and the user side provides service via FXS interfaces. A single voice channel is compressed into a 64Kbit/s bit stream using ITU-T G.711 A-law, with an audio range of 300 Hz to 3400 Hz and a loop current of 20mA per channel.
The voice interface impedance is a three-element complex impedance of 200Ω+560Ω//0.1μF. Voice channels are organized into time slots according to the PCM30/32 format and then multiplexed into the 2.5Gbps channel. The peer equipment restores them to analog voice using the same format. Both FXO and FXS interfaces support caller ID (CID) and can directly connect to analog telephones, fax machines, and switching equipment. Along the entire link, telephone, E1, and gigabit Ethernet share the same optical fiber for transmission, and services do not interfere with one another through channel partitioning.
Technical Specifications
The parameters of the IDM 300GP telephone optical multiplexer are listed in three groups: optical interface, service interface, and power supply environment. During selection, first determine the optical module according to transmission distance, then determine card slots and interface quantities according to the service list. As a product showcase model under Raytrans, the specifications in the table below are taken from product documentation and can be directly cited in configuration lists and tender responses; on-site settings should be verified against the actual interface types of the peer equipment.
Optical Interface Parameters
The optical port is an SFP slot, with a receive/transmit rate of 2.5Gbps. 20Km is the standard transmission distance, and the link budget is calculated based on transmit optical power and receiver sensitivity. Wavelengths are configured in transmit/receive pairs; for long-distance or WDM scenarios, long-distance optical modules can be installed.
| Item | Parameter/Specification | Description/Applicable Conditions |
|---|---|---|
| Interface type | SFP | Optical module selected according to transmission distance and wavelength |
| Fiber mode | Single-mode (multimode optional) | Selected according to on-site optical cable conditions |
| Receive/transmit rate | 2.5Gbps | Optical line rate |
| Receive/transmit wavelength | 1310nm/1550nm | Configured in transmit/receive pairs |
| Transmit optical power | -12～-6dBm | Output optical power at the transmit side |
| Receiver sensitivity | Better than -32dBm | Lower limit of normal operating optical power at the receive side |
| Transmission distance | 20Km | Long-distance optical modules can be installed for longer transmission |
Figure 2: IDM 300GP telephone optical multiplexer rear panel layout with SFP optical interface, 8 groups of E1, and dual gigabit Ethernet interfaces
Ethernet, E1, and Voice Interface Parameters
The Ethernet, E1, and FXO/FXS interfaces constitute the service access side of the site, and parameters are listed separately by interface. E1 impedance and Ethernet rate are set on site according to the peer equipment, and voice interface parameters determine the connection quality between telephones and switches.
| Item | Parameter/Specification | Description/Applicable Conditions |
|---|---|---|
| Ethernet interface type | RJ-45 | Electrical interface, 2 physically isolated channels |
| Ethernet transmission rate | 10M/100M/1000M | Line rate 1000M, adaptive |
| Ethernet standard protocol | Supports IEEE802.3 | Operating mode full/half duplex/adaptive |
| E1 bit rate | 2.048Mbps | Line code HDB3 |
| E1 standard protocol | Supports ITU-T G.703 | Impedance 75 Ω/120 Ω selectable |
| E1 frame structure and signaling | PCM30/32, channel-associated signaling | Transparent transmission mode, original frame structure not rewritten |
| E1 interface configuration | 8 groups | 4 groups 75 Ω unbalanced + 4 groups 120 Ω balanced |
| Voice audio range | 300 Hz～3400 Hz | Compression ITU G.711 A-law |
| Voice interface impedance | Three-element complex impedance 200Ω+560Ω//0.1μF | Loop current 20mA per channel |
| Caller ID | Supported on both FXO and FXS | Connects to analog telephones, fax machines, and switching equipment |
Optional Narrowband Data Interface Parameters
Codirectional 64K, EM2/4-wire, V.24, and V.35 interfaces are selected according to the service list and are used for relay protection signals, telecontrol channels, serial port data, and leased line equipment access. The parameters of each interface and the recommendations they comply with are listed item by item in the table below; verify against the peer equipment interface type before wiring.
| Interface | Parameter/Specification | Description/Applicable Conditions |
|---|---|---|
| Codirectional 64K | Line code G.703, bit rate 64Kbps, balanced impedance 120 Ω | Fully complies with ITU G.703 recommendation |
| EM2/4-wire | Audio 300 Hz～3400 Hz, balanced impedance 600 Ω, ITU G.711 A-law | Return loss no less than 18 dB |
| V.24 | Asynchronous ≤9600bps, synchronous 64Kbps | Electrical characteristics comply with CCITT V.28 protocol |
| V.35 | RJ-45, n×64Kbps (n=0～31) | Complies with ITU-T V.35 recommendation; terminal interface complies with ISO2593 |
Power Supply, Environment, and Chassis
The power supply mode is AC220V or DC-48V, with overall power consumption ≤90W. Both AC power in equipment rooms and DC -48V communications power conditions can be directly connected. The operating temperature is -10℃～+50℃ and the relative humidity is 0～95% (non-condensing), making it suitable for indoor equipment rooms and attended communications stations.
| Item | Parameter/Specification | Description/Applicable Conditions |
|---|---|---|
| Power supply mode | AC220V/DC-48V | Selected according to equipment room power conditions |
| Overall power consumption | ≤90W | In full configuration |
| Operating temperature | -10℃～+50℃ | Indoor equipment rooms and communications stations |
| Relative humidity | 0～95% (non-condensing) | Avoid condensing environments |
| Dimensions | 482×266×270mm (Length×Depth×Height) | 19-inch standard 6U chassis |
How the card-based structure expands from 30 channels to 300 channels
Capacity expansion is based on the number of voice channels actually activated at the site. Service cards are inserted in steps of 30 channels, so there is no need to populate all slots initially. When all 10 service card slots are populated, the full configuration of 300 channels is reached. The 2 main control card slots and 2 power card slots are configured as standard, so the configuration accounting for the 14 card slots is closed. Project implementation proceeds in the following order, with installation, cabling, and service card insertion carried out as three separate steps.
- Chassis positioning: secure the chassis in the cabinet within a 19-inch 6U space, and position the backplane and wiring area according to the construction drawings.
- Optical path termination: configure SFP (small form-factor pluggable) modules in pairs according to transmission distance and wavelength, and terminate single-mode fiber (multi-mode optional) before connecting to the optical port.
- Insert the main control card and power cards: insert the main control card and 2 power cards, and select AC220V or DC-48V power supply according to on-site conditions.
- Insert service cards according to the voice channel list: each service card adds 30 voice channels; inserting 10 cards gives the full configuration of 300 channels.
- Interface matching: connect FXO to the exchange side and FXS to user telephones; select 75 Ω unbalanced or 120 Ω balanced for the 8 groups of E1 interfaces; connect the 2 gigabit interfaces to data equipment.
- Power-on verification: observe the panel alarm indications of each card slot, verify the number of activated voice channels per card and the interface correspondence, and record the results for archiving.
After voice channel growth, capacity expansion is still performed by inserting cards: the chassis with vacant service card slots continues to be used, and cards are added in 30-channel steps, while the configuration of the chassis, backplane, main control card and power cards remains unchanged. Capacity planning is calculated against the upper limit of 300 channels per chassis; beyond this scale, the number of chassis and the site distribution are planned separately, and capacity expansion does not require replacing the complete unit. This card-based expansion feature gives this telephone optical multiplexer good capacity flexibility at sites where multi-service optical multiplexers and PDH optical multiplexers are used together.
How Far Can 2.5Gbps Single-Fiber 20Km Transmit, and What If the Distance Is Insufficient?
The standard model is configured for 20Km. The link budget is derived from a transmit optical power of -12 to -6 dBm and a receiver sensitivity better than -32 dBm; in engineering, the margin is calculated after deducting the losses of the optical modules at both ends, the mating connectors and the optical cable attenuation item by item. Single-fiber bidirectional transmission occupies only one fiber core, saving half the number of cores in long-distance fiber leasing scenarios.
When the distance exceeds 20Km, replacing the long-distance optical module extends the transmission distance without changing the chassis or service cards. Sites with high link reliability requirements can use dual-fiber mutual backup networking, switching to the backup optical path when the primary optical path fails; multi-site projects can also work with other equipment to form chain networks, ring networks and point-to-multipoint star networks. As an optical multiplexer manufacturer, Raytrans can provide corresponding distance calculation and networking recommendations for different models such as gigabit network optical multiplexers, multi-service optical multiplexers and PDH optical multiplexers, based on the actual link conditions of government private network optical fiber communication solutions and military emergency communications vehicle solutions.
Figure 3: IDM 300GP telephone optical multiplexer dual gigabit 8E1 and 300-channel telephone point-to-point and chain network networking schematic
Typical Application Scenarios
As a typical multi-service optical multiplexer product showcase, the IDM 300GP telephone optical multiplexer addresses three types of scenarios: electric power private networks, rail transit communication, and military and government private networks. Their common features are distributed sites, mostly unattended, and the need for voice and data to be backhauled over the same path. The following three scenarios are described respectively in terms of service access mode, card slot configuration and O&M actions, to facilitate configuration verification by project type.
Electric Power Private Network: Substation Dispatch Telephone and Telecontrol Data Backhaul over the Same Fiber
Electric power private networks deploy sites along the line. Substations must not only ensure continuous availability of dispatch telephones but also backhaul telecontrol data and in-station surveillance to the dispatch center. On the substation side, the IDM 300GP telephone optical multiplexer provides centralized access: dispatch and administrative telephones are provisioned through FXS interfaces, the E1 trunk to the dispatch center is extended through 8 groups of E1 transparent transmission interfaces, and telecontrol data and surveillance backhaul run over 2 physically isolated gigabit interfaces respectively. As a product of Raytrans, a professional optical multiplexer manufacturer, the device also offers good adaptability in government private network optical fiber communication solutions.
The 2 gigabit interfaces are isolated at the physical layer, keeping the boundaries of the telecontrol service network and the video surveillance network independent on the same device, so that VLAN partitioning is no longer needed to distinguish services. The number of voice channels is configured by service cards in tiers according to site traffic: small sites insert a few service cards first, hub sites are planned for 300 channels, and the card slots leave room for future growth.
Rail Transit: Telephone and E1 Channel Extension at Stations and Section Duty Points
Stations, depots and section duty points of rail transit are distributed along the line. The number of telephones varies greatly with station class, and E1 channels are also needed between stations to carry dedicated communication services. The IDM 300GP telephone optical multiplexer configures service cards in a card-based manner according to site traffic, uses the 8 groups of E1 transparent transmission interfaces for inter-station trunk extension, and uses the 2 gigabit Ethernet interfaces to carry station service data and video backhaul.
The 19-inch 6U chassis facilitates unified installation in the communications equipment room. Spare card replacement at sites along the line does not require taking the complete unit out of service, and maintenance is performed by card slot. Section duty points are usually unattended; 1+1 mutual backup power supply and hot-swappable card slots confine power supply and single board failure to the single card, reducing attendance on site caused by single card anomalies.
Military and Government Private Networks: Independent Networking of Station Telephones and Private Network Data
Military and government private networks have clear requirements for call availability and link independence, and communications between stations, duty posts and command nodes are organized independently over the private network. In private networks, the IDM 300GP telephone optical multiplexer provides centralized access on the station side: the exchange side connects to switching equipment through FXO interfaces, the user side completes subscriber line provisioning through FXS interfaces, and voice is encoded with G.711 and transmitted over the 2.5Gbps channel, sharing one fiber with E1 trunks and data services. In the military emergency communications vehicle solutions provided by Raytrans, this type of optical multiplexer product can also be used as site-side access equipment.
The 2 physically isolated gigabit interfaces let private network services and supporting networks each use an independent channel, so calls and data do not contend with each other. On-duty personnel locate the faulty card by the panel alarm indication and the card slot number, and replacement is completed by preparing a spare card according to the number, without waiting for the manufacturer to attend on site; site maintenance actions are mainly card replacement.
Conclusion
The dual gigabit 8E1 telephone optical multiplexer packs 2 physically isolated gigabit Ethernet interfaces, 8 groups of E1 transparent transmission interfaces and FXO/FXS voice channels with caller ID into one 6U card-based chassis, completing voice, trunk and data backhaul over one 2.5Gbps fiber, with single-fiber 20Km meeting long-distance private network networking requirements. The card-based structure of 30 channels per card and 300 channels in full configuration allows both capacity expansion and card replacement to be performed by card slot.
The IDM 300GP telephone optical multiplexer provides centralized access on the site side in electric power private networks, rail transit communication and military and government private networks, and 1+1 mutual backup power supply and hot-swappable card slots confine the impact of failures to the single card. As an optical multiplexer manufacturer, Raytrans can provide corresponding configuration recommendations for government private network optical fiber communication solutions and military emergency communications vehicle solutions. The specific card slot configuration, interface type and optical module selection are verified against the site service list, and the parameters are subject to the manufacturer's technical documentation and commercial confirmation.
