STM-1 Synchronous Digital Multiplexer

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RAD R-STM-1E STM-1 Synchronous Digital Multiplexer 


  • SDH transmission solution for access networks, expands local loops to 60 km/37 miles

  • Low power consumption and high reliability optimized for installation in outdoor cabinets

  • Flexible configuration as an STM-1 terminal or Add&Drop Multiplexer (ADM) with full cross-connectivity and PDH interfaces

  • Supports centralized management, including configuration, service, performance, security and fault management

  • Integrated management system also supports Multiservice Access Platform (MAP) equipment

  • Accurate transfer of timing to access equipment

  • Low cost per line

  • Flexible configurations

  • R-STM-1E is a Synchronous Digital Hierarchy (SDH) multiplexer for deployment in the local loop.


  • R-STM-1E can be deployed in access nodes as a Terminal Multiplexer (TM) or an Add & Drop Multiplexer (ADM). It enables expansion of the local loop up to 60 km/37 miles, creating a transmission layer fully compatible with regional and national SDH networks.

  • R-STM-1E is available with either standard G.703 coaxial or fiber optical short/long haul aggregate interfaces.

  • The SDH transmission supports a full range of access systems, including Remote Subscriber Units (RSUs), Digital Line Carriers (DLCs), Digital Cross-Connect (DACS), and service multiplexers.

  • R-STM-1E is fully compatible with 34 Mbps (E3) and 45 Mbps (T3) PDH signals, SDH microwave radio relays, and existing SDH infrastructure.

  • R-STM-1E supports the whole range of SDH network topologies:

    • Point-to-Point

    • Chain

    • STM-1 ring / folded ring

    • STM-4/16 ring / STM-1 structured ring-star and ring-ring.

  • The interface capacity of R-STM-1E can be expanded from its 21x2 Mbps basic configuration by adding extension modules (ordering options), to any of the following:

    • 63x2 Mbps (63xE1)

    • 3x34 Mbps (3xE3)

    • 3x45 Mbps (3xT3)

  • DXC-STM-1, a hybrid unit combining the R-STM-1E multiplexer and the DXC digital cross-connect in a single integrated chassis, is also available. It features both DXC 1/0 cross-connect and SDH ADM capabilities (see the DXC-STM-1 folder).

  • The compact size and low power consumption of R-STM-1E allow easy rack or wall installation on customer premises, in telecommunications buildings, or in outdoor cabinets.

  • A comprehensive array of installation accessories support vertical/horizontal rack installation, wall mounting, etc.

  • R-STM-1E features a centralized management application, to facilitate management of the access network. The application combines both the powerful RADView and the SDH transmission layer network management applications. The centralized network management application uses embedded management channels for communication with remote access equipment. Centralized management enables the building of flexible, responsive and optimized SDH access networks to fit any customer's needs.

  • The 2 Mbps output signals of R-STM-1E can be resynchronized by the R-STM-1E multiplexer clock. In addition, pointer justification events can be filtered out, eliminating phase hits. This creates an accurate signal, clear of phase hits and suitable for synchronization of access equipment. Since the SDH network is usually synchronized by the national synchronization network, this accurate timing is transferred to the access equipment



? SDH Level

STM-1 (155.520 Mbps)

? Multiplexing Structure

Complies with Figure 1.1 in G.709 standard

? Cross-Connect Level

VC-12 or multiples

? Error Performance

Complies with G.826 - High grade

? Jitter

Aggregate line: complies with G.783, G.823, G.958

Tributary line: complies with G.783, G.823

? Diagnostics

Performance monitoring according to G.826, G.784

External alarms

? Indicators

ACT ? normal operation
FLT ? malfunction detected or software downloading
PRG ? management accesses NVM card
ALM ? transmission alarm
ACK ? current alarms acknowledged
LASER ON ? optical aggregate is transmitting

? Power Supply

Input voltage: -35 VDC to -75 VDC

Nominal power source: -48 VDC to -60 VDC

? Physical

Compatible with ETSI rack
Height: 300 mm / 11.8 in
Width: 90 mm / 3.5 in
Depth: 220 mm / 8.7 in
Weight: 2.0 kg / 4.4 lb


? Physical Level

G.703, paragraph 12

? Line Code


? Bit Rate

155.520 Mbps

? Connectors



? Physical Level

G.957, Table 2 ? optical aggregate

? Transmission Line

Dual fiber optic cable

? Operating Wavelength

As per G.707, G.958, see Table 2.

? Bit Rate

155.520 Mbps

? Connectors


? Optical Transmit/Receive


See Table 2.


2 Mbps (E1)

? Physical Level

G.703, paragraph 6

? Bit Rate

2.048 Mbps

? Line Code


? Frame


? Connectors


34 Mbps (E3)

? Physical Level

G.703, paragraph 8

? Bit Rate

34.368 Mbps

? Line Code


? Frame


? Connectors

DIN 1.6/5.6 MS

45 Mbps (T3)

? Physical Level

ANSI T1.105.03-1994

? Bit Rate

44.736 Mbps

? Line Code


? Connectors

DIN 1.6/5.6 MS


? Complete Network Management

RADView software on dedicated SUN workstation

? Network Element Monitoring

Element Manager software on PC or laptop 




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