IDM OMP2000-4E1-30E Ultra-Broadband Integrated Service Optical Multiplexing Equipment, 30 Telephone Lines, 2 Gigabit Ethernet Ports, 4E1

The 30-channel telephone 2-channel isolated gigabit optical multiplexer is an ultra-broadband integrated service optical multiplexing equipment model IDM OMP2000-4E1-30E, developed by Beijing Ruiguang Jiyuan Digital Technology Co., Ltd. (Raytrans). As a mature PCM equipment, it is used to simultaneously transmit 30 telephone channels, 4 E1 leased lines and 2 physically isolated line-rate gigabit Ethernet channels over a pair of optical fibers, meeting the product showcase requirements of unified multi-service access.

The IDM OMP2000-4E1-30E uses 2.5G optical fiber transmission bandwidth and adopts the PCM30/31 format. Telephones are encoded into 64 Kbps voice channels using ITU-T G.711 A-law, E1 is transparently transmitted at 2048 Kbps with HDB3 line code in accordance with ITU-T G.703, and Ethernet is forwarded at line rate in accordance with IEEE 802.3. The three service types each occupy an independent channel and do not contend with one another. This integrated service access device integrates telephone access, E1 transparent transmission and Ethernet isolation, fully demonstrating the integration advantages of optical multiplexing equipment in multi-service scenarios.

The two optical fibers back up each other; when the primary link fails, services are switched to the backup fiber for transmission. On the power supply side, dual power supply access is provided with DC-48V and AC220V, and the overall power consumption is ≤100 W. One device can replace the previous practice of stacking multiple telephone optical multiplexers, E1 multiplexing equipment and isolation bridges, leaving only one set of cabling in the site equipment room. As a professional optical multiplexer manufacturer, Raytrans offers this PCM equipment for a wide range of scenarios with stringent reliability requirements, such as government private network optical fiber communication solutions and military emergency communications vehicle solutions.

Key Specifications at a Glance: 2.5 Gbps optical fiber (SFP, 1310 nm/1550 nm) · 30 telephone channels (FXO/FXS/magneto, ITU-T G.711 A-law) · 2 physically isolated line-rate gigabit ports (2000 M in total) · 4 E1 transparent channels (G.703, 75 Ω or 120 Ω, HDB3, PCM30/31) · dual-fiber mutual backup · dual power supply redundancy DC-48V/AC220V · overall power consumption ≤100 W

Figure 1: Front view of the IDM OMP2000-4E1-30E, showing the SFP optical ports, power and alarm indicator LEDs, and function control switches

What is the 30-channel telephone 2-channel isolated gigabit optical multiplexer

The 30-channel telephone 2-channel isolated gigabit optical multiplexer refers to an integrated service access device that provides 30 telephone interfaces, 2 physically isolated line-rate gigabit Ethernet ports and E1 channels in a single PCM equipment, and uplinks over a 2.5G optical fiber link. Voice, leased lines and data each occupy independent channels and do not take up bandwidth from one another on the optical path; once the two ends are commissioned as a pair, services are interoperable as they are.

The optical ports of the IDM OMP2000-4E1-30E use a pluggable SFP structure, with single-mode as the standard configuration and multi-mode modules selectable for short-distance cabling. The optical fiber rate is 2.5 Gbps and the wavelength is 1310 nm/1550 nm. The transmit optical power of -1 to -3 dBm and the receiver sensitivity of better than -24 dBm together determine the link loss budget; calculating on this basis is more aligned with on-site conditions than selecting directly by nominal distance.

The telephone interfaces can be FXO, FXS or magneto type, with a telephone audio range of 300 Hz to 3400 Hz, ITU-T G.711 A-law compression, a three-element complex impedance of 200 Ω + 560 Ω//0.1 μF, and a loop current of 25 mA per channel, and can connect to SPC exchanges, analog trunks and magneto telephones. E1 is framed at 2048 Kbps with HDB3 and PCM30/31, and the transparent transmission mode does not change the time slot content.

How does one 1U device carry 30 telephone channels, 2 isolated gigabit ports and 4 E1 channels simultaneously

The IDM OMP2000-4E1-30E concentrates the subscriber interfaces formerly spread across multiple devices into a single 1U chassis, so that 30 telephone channels, 4 E1 transparent channels and 2 physically isolated gigabit ports can operate online simultaneously. As a PCM equipment designed for multi-service scenarios, its interface capabilities and applicable conditions for each function are listed in the table below; the specific interface types and quantities are determined by the order configuration.

Function	Description
30-channel telephone access	FXO, FXS or magneto interfaces selectable; audio range 300 Hz to 3400 Hz; ITU-T G.711 A-law compression; loop current 25 mA per channel; can directly connect to SPC exchanges, analog trunks or magneto telephones
4-channel E1 transparent transmission	Provides 1 to 4 E1 channels; bit rate 2048 Kbps; line code HDB3; compliant with ITU-T G.703; impedance 75 Ω/120 Ω selectable; frame structure PCM30/31; transparent transmission does not change the time slot content
Voice and E1 multiplexing	30 telephone channels and E1 are multiplexed into the 2.5 Gbps optical link over their respective channels and reach the peer end simultaneously over one optical fiber; the two service types do not take up bandwidth from each other
2 isolated gigabit ports	2 physically isolated line-rate 1000 M Ethernet ports, 2000 M in total; independent port bandwidth and security zoning; compliant with IEEE 802.3; full/half duplex/adaptive
Dual-fiber mutual backup	Two optical fibers, one primary and one backup; when the primary link is cut or the optical module degrades, services are automatically switched to the backup link, and telephone and E1 connections do not need renegotiation
Dual power supply redundancy	Supports DC-48V, AC220V and dual power supply access; when a single power supply fails, the other continues to supply power; overall power consumption ≤100 W

The 30 voice channels each occupy an independent channel within the device, and one off-hook call does not affect the call quality of the other voice channels. The telephone interfaces are encoded with ITU-T G.711 A-law and provide a loop current of 25 mA per channel, so no additional conversion equipment is needed when connecting to SPC exchanges and magneto telephones, and the existing telephones and patch panels can continue to be used.

The E1 interfaces comply with ITU-T G.703, with HDB3 line code and 75 Ω/120 Ω selectable impedance, and do not change the time slot content in transparent transmission mode. The data configurations of dispatch automation equipment and protection devices at the peer end can be retained as they are, and no re-mapping of time slots is required between the two sites.

Figure 2: Rear panel of the IDM OMP2000-4E1-30E, showing the layout of the 30 telephone interfaces, 4 E1 ports and 2 isolated gigabit Ethernet ports

How do dual-fiber mutual backup and dual power supply keep services uninterrupted

Dual-fiber mutual backup configures the transmission channels in both directions as two optical fiber links, one primary and one backup. Services are normally transmitted over the primary link while the backup link remains in hot standby. When the primary link is cut, the optical module degrades or the peer end becomes abnormal, the device detects the abnormal received optical power and automatically switches services to the backup link, and telephone and E1 connections do not need renegotiation.

Redundancy resides in two layers, the optical path and the power supply, and does not rely on upper-layer protocol rerouting; protection switching does not discriminate between service types. When any segment of optical fiber in a chain network, ring network or point-to-multipoint star network is interrupted, services are still transmitted along the spare fiber core, so substations, railway lines and classified equipment rooms do not need a separate protection switching protocol for this purpose.

On the power supply side, three modes are provided: DC-48V, AC220V and dual power supply. The -48 V DC commonly used in communications equipment rooms and the station AC can each occupy one feed, and when a single power supply fails, the other continues to supply power. During wiring, first check that the equipment room power supply system matches the equipment markings, then check that the grounding and terminal crimping are secure, and then power on and observe the power and alarm indications.

The device uses a standard 19-inch 1U chassis and is equipped with function control switches and alarm indicator LEDs, so that received optical power, power supply and service status can be seen clearly at the front of the cabinet. When a site is unattended for a long time, the panel alarm indication is the direct basis for on-site troubleshooting; O&M personnel first check the indicator LEDs and then measure the optical power, giving a clear troubleshooting sequence.

Figure 3: Point-to-point networking diagram of the IDM OMP2000-4E1-30E with dual-fiber mutual backup

How do the 2 physically isolated gigabit ports divide ports to ensure service security

The 2 physically isolated gigabit ports ensure security because each port uses an independent channel inside the device, neither sharing bandwidth nor sharing forwarding resources. The IDM OMP2000-4E1-30E provides 2 physically isolated line-rate gigabit Ethernet ports, with a line rate of 1000 M per port and 2000 M in total; one port running at full load does not affect forwarding on the other.

During deployment, services are assigned to different ports according to network security levels. The principle is that important services occupy dedicated ports and services of the same type are grouped on the same port, which facilitates both zoned management and individual maintenance. The common assignments of the two gigabit ports at a site are as follows; the specific grouping is adjusted according to the site network plan:

• Video surveillance and production data: occupy 1 gigabit port; camera streams and in-station production data are transmitted back separately and do not share traffic with office traffic;
• Dispatch and management network: occupy 1 gigabit port; carry real-time data between the dispatch master station and the station end as well as O&M terminal access.

The networks are physically isolated and invisible to one another, and servicing one port separately does not affect other services. Compared with connecting multiple services to the same ordinary switch, this approach gives clearer network zoning boundaries and better meets the zoning management requirements of the electric power, rail transit and classified industries.

The gigabit ports comply with IEEE 802.3, support 10M/100M/1000M adaptive rates and full/half duplex/adaptive negotiation, and can directly connect to the uplink ports of switches at the site. When LAN switching with multiple interconnected ports is required, connect an Ethernet switch after each port, and the isolation characteristics remain unchanged.

Technical Specifications

As a PCM equipment designed for multi-service carrying in private networks, the IDM OMP2000-4E1-30E has core parameters covering six parts: optical interfaces, E1 interfaces, Ethernet interfaces, telephone interfaces, power supply and environment. The key specifications are listed in the table below. The values are taken from Raytrans manufacturer product documentation; during project selection, calculate according to the actual line and service volume, and determine the optical module distance grade separately based on the link loss budget.

Item	Parameter/Specification	Description/Applicable Conditions
Optical interface type	SFP	Pluggable optical module, facilitating replacement by distance and spare parts stocking
Optical fiber rate	2.5Gbps	Shared by telephone, E1 and isolated gigabit services
Fiber mode	Single-mode (multi-mode optional)	Selected according to line distance and existing fiber core conditions
Wavelength	1310nm/1550nm	Two wavelengths selectable
Transmit optical power	-1~-3dBm	Typical single-mode value; subject to actual measurement with an optical power meter
Receiver sensitivity	Better than -24dBm	The link loss budget can be calculated on this basis
Optical fiber redundancy	Dual-fiber mutual backup	Two optical fibers, one primary and one backup; services are switched automatically
Number of E1 channels	1~4	Configured according to the site service list
E1 bit rate	2048Kbps	Line coding HDB3
E1 standard protocol	Supports ITU-T G.703	Standard E1 interface specification
E1 impedance	75 Ω/120 Ω	Selected according to the interface of the interconnected equipment
E1 frame structure	PCM30/31	Primary group frame structure
E1 mode	Transparent transmission	Services are transmitted as they are, without changing the time slot content
Number of telephone interfaces	30	FXO, FXS or magneto type optional
Telephone audio range	300 Hz~3400 Hz	Telephone voice channel bandwidth
Telephone audio impedance	Three-element complex impedance 200 Ω+560 Ω//0.1 μF	Telephone subscriber line interface standard
Compression	ITU G.711 A-law	64Kbps PCM encoding
Loop current	25mA per channel	Feeding capability of each voice channel
Ethernet interface type	RJ45 connector	Standard Ethernet electrical port
Ethernet transmission rate	10M/100M/1000M	Complies with IEEE802.3; adaptive half-duplex/full-duplex
Ethernet port configuration	2 physically isolated wire-speed 1000M	2 independent bandwidths, 2000M in total
Ethernet physical isolation	Independent port channels	No bandwidth or forwarding resources shared between services
Chassis structure	Standard 19-inch 1U	Facilitates rack installation in a cabinet
Power supply mode	DC-48V / AC220V / dual power supply	Dual power supply access improves power supply reliability
Overall power consumption	≤100W	Unit value including service interfaces and optical modules
Operating temperature	0℃～40℃	Equipment room or temperature-controlled cabinet environment
Humidity	≤90% (non-condensing)	Upper limit of relative humidity

The optical port rate of 2.5Gbps, the transmit optical power of -1~-3dBm and the receiver sensitivity better than -24dBm jointly determine the link budget. This integrated service access device adopts PCM multiplexing technology. The 300 Hz~3400 Hz audio range of the telephone interface and the G.711 A-law encoding determine voice channel compatibility. During selection, compare item by item against the interface type and signaling of the opposite end.

Typical Application Scenarios

The applications of IDM OMP2000-4E1-30E are concentrated in three types of sites: electric power private networks, rail transit, and military and government private networks. The common requirement is to send telephone, E1 leased lines and isolated data back to the center over one optical fiber, while not accepting long downtime. As a flagship product of the optical multiplexer manufacturer Raytrans, the device plays the role of integrated service access in the above scenarios.

Electric Power Private Networks

Substations, power plants and distribution automation sites need to simultaneously transmit dispatch telephone, automation E1 leased lines and in-station data networks. Each site is equipped with one IDM OMP2000-4E1-30E, which uses one 2.5Gbps optical fiber to multiplex inter-station dispatch audio, E1 leased-line channels and isolated Ethernet for transmission; at the central side, one optical fiber can collect all services.

The telephone interface directly connects to dispatch voice channel equipment with G.711 A-law and a loop current of 25mA per channel, and 4-channel E1 transparent transmission frees the opposite-end automation equipment from configuration changes. With dual-fiber mutual backup enabled, if any section of the inter-station optical cable is interrupted, telephone and E1 services are automatically switched to the backup link, and the dispatch console does not need to redial.

Rail Transit

Stations, depots and tunnel sections of metro and conventional railways need to aggregate telephone, E1 trunks and network data along the line back to the central equipment room. At each site along the line, one IDM OMP2000-4E1-30E simultaneously accesses 30 voice channels, 4 E1 channels and 2 isolated gigabit networks, and sends them to the center over a 2.5Gbps optical fiber.

The device supports DC-48V and AC220V dual power supply and has an overall power consumption of ≤100W, suitable for long-term operation in unattended equipment rooms along the line. The 2 isolated gigabit ports let surveillance, office and dispatch networks each use independent ports; servicing one port does not affect the other networks, and the zone boundaries are consistent with the network management requirements of railway communications.

Military and Government Private Networks

Field training sites, emergency command posts and government classified equipment rooms emphasize one terminal, many uses and reliable operation. One IDM OMP2000-4E1-30E PCM equipment simultaneously carries 30 telephone channels, 4 E1 channels and 2 isolated gigabit networks, reducing the number of devices and cable laying; during relocation and deployment, only one 1U device needs to be moved. Raytrans can provide adapted configurations for government private network optical fiber communication solutions and military emergency communications vehicle solutions, meeting the rapid deployment requirements of command and dispatch scenarios.

Dual-fiber mutual backup ensures that command and dispatch telephone is not interrupted when a single optical fiber fails. Dual power supply supports both DC-48V and AC220V equipment room conditions, facilitating operation from station AC power or communications DC power; with overall power consumption of ≤100W, the burden on field storage batteries is lower.

Figure 4: Service access scenario of IDM OMP2000-4E1-30E rack-mounted in cabinets at electric power and rail sites

Differentiated Value: What Dual-Fiber Mutual Backup and 2 Isolated Gigabit Ports Bring

The differentiated value of IDM OMP2000-4E1-30E is concentrated in three aspects: optical path redundancy, service convergence and network isolation. The capabilities and on-site benefits corresponding to the four short selling point labels are shown in the table below; during selection, compare them row by row against service requirements.

Short selling point labels and differentiated selling points	Value to users
Dual-fiber mutual backup: two optical fibers, one primary and one backup; when the primary link is interrupted, services are automatically switched to the backup link	Telephone and E1 services are not interrupted when a private network link fails; the backup fiber remains hot standby, and O&M personnel do not need to go on site to change patch cords
Dual power supply redundancy: DC-48V and AC220V dual power supply access, overall power consumption ≤100W	Adapts to both DC power in communications equipment rooms and station AC power, suitable for long-term operation at unattended sites
30 telephone channels: a single unit provides 30 FXO/FXS/magneto voice channels, G.711 A-law, loop current 25mA per channel	Voice and leased lines are consolidated into the same 1U device, eliminating separate voice channel equipment and patch panels, with equipment room space and cables reduced accordingly
2 isolated gigabit ports: 2 physically isolated wire-speed gigabit ports, 2000M in total	Surveillance, office and dispatch data each use independent ports; one port running at full load does not take bandwidth from another, and security zone boundaries are clear

The 2.5G optical fiber bandwidth is the shared bearer foundation for the above capabilities. The 30 telephone channels and 4 E1 channels occupy narrowband time slots, while the 2 isolated gigabit ports each use independent channels; the two types of services do not drag each other down even when online at the same time. For service capacity expansion, simply add interfaces to the existing configuration; there is no need to lay another optical cable for a new type of service. For users interested in product showcase and PCM equipment selection, Raytrans can provide a complete optical multiplexer product line and technical support for government private network optical fiber communication solutions and military emergency communications vehicle solutions.

How to Select a 30-Channel Telephone 2-Isolated-Gigabit Optical Multiplexer

To select a 30-channel telephone 2-isolated-gigabit optical multiplexer, check the four items of number of service channels, optical fiber conditions, redundancy requirements and power supply environment one by one to determine the configuration. Once all four items are checked against the site list, the model and interface combination are basically clear. The four check items and common practices are as follows:

1. Count the number of service channels: confirm the number of telephone channels (IDM OMP2000-4E1-30E provides 30, with FXO/FXS/magneto optional), the number of E1 channels (1~4) and the number of isolated gigabit ports (2). If the interface type or quantity does not match, change the model or add interfaces.
2. Check optical fiber conditions: confirm single-mode or multi-mode and whether the wavelength is 1310nm or 1550nm; calculate the loss budget based on the transmit optical power of -1~-3dBm and the receiver sensitivity better than -24dBm, then determine the distance grade of the SFP optical module.
3. Confirm redundancy requirements: enable dual-fiber mutual backup for lines where inter-station optical cables are prone to damage, with the primary and backup optical fiber channels as hot standby for each other; where only a single optical cable is available, at least reserve spare optical modules and spare parts.
4. Check power supply and environment: DC-48V, AC220V or dual power supply must match the site power supply; overall power consumption ≤100W, operating temperature 0℃～40℃, humidity ≤90% (non-condensing). Installation in a standard equipment room or a temperature-controlled cabinet is recommended.

As a 2.5G optical multiplexing equipment, IDM OMP2000-4E1-30E concentrates its configuration options on interface types and optical module grades. The same model can be equipped with FXO, FXS or magneto telephone interfaces according to the site list, or only part of the E1 channels can be configured, avoiding payment for idle interfaces. This PCM equipment has mature applications in government private network optical fiber communication solutions and military emergency communications vehicle solutions; during selection, it can be evaluated together with the government private network optical fiber communication solutions and military emergency communications vehicle solutions provided by Raytrans.

Conclusion

The 30-channel telephone 2-isolated-gigabit optical multiplexer IDM OMP2000-4E1-30E aggregates 30 telephone channels, 4-channel E1 transparent transmission and 2 physically isolated wire-speed gigabit Ethernet interfaces onto one 2.5Gbps optical fiber. Dual-fiber mutual backup switches services to the backup link when the optical fiber is interrupted, and DC-48V/AC220V dual power supply and ≤100W overall power consumption adapt to various equipment room conditions.

During selection, first count the number of telephone, E1 and isolated gigabit ports, then calculate the link loss and check the power supply and environmental conditions; include the number of sites at both ends and the optical cable conditions in the list so that quotation and configuration can be aligned. For product showcase, networking solutions and quotations, provide the site list and line conditions to Beijing Ruiguang Jiyuan Digital Technology Co., Ltd.