Mini-M/M4 NCS/LES Emulator

The Square Peg Communications Inc. (SPCI) mini-M/M4 Physical Layer Tester (MPLT) supports the testing of MESs for the various flavours of Inmarsat-M4 services including mini-M, GAN, Fleet and Swift64.

The Network Coordination Station / Land Earth Station (NCS/LES) emulator is a software add-on to the MPLT which provides a simple and flexible means of testing MES operation and the operation of end-to-end applications without incurring expensive airtime charges. It can be easily used to test basic terminal operation and standard voice calls as well as end-to-end applications running over ISDN such as TCP/IP for web browsing, email and file transfer or other ISDN applications such as videoconferencing.

The emulator acts as both the NCS and the LES. It transmits NCS and LES TDM channels and receives the MESRQ and MESRP signalling channels from the MES under test. The remaining MPLT channels are used for SCPC data when calls are established.

The emulator maintains a list of valid MESs and handles calls to / from any MES on the list.

Multiple simultaneous calls and multiple MESs are supported, depending upon the hardware available. The emulator supports the establishment of mini-M voice and ISDN calls in both the to- and from-mobile directions, including dual-hop mobile-to-mobile calls. It also supports looped back voice calls.

Once a call is established, an end-to-end test of the application or service can be carried out. For mini-M voice calls, the MPLT provides one or more mini-M codec interfaces. SPCI Voice Codec Units (VCUs) are connected to these interfaces. The codec provides a standard 2wire or 4wire analog phone connection, enabling end-to-end voice conversation to take place between the LES emulator and the MES handset.

For ISDN calls, an interface card installed in the CU provides an ISDN Basic Rate Interface (BRI), otherwise known as the S/T interface, operating in Network Termination (NT) mode. Various types of ISDN devices can be connected to the NT interface, including routers (e.g., for end-to-end IP connectivity) or an ISDN Terminal Adaptor (e.g., for PCM clear voice calls).

  • NCS/LES Emulator Configuration

  • Emulator Components

    PLT Channel Unit (CU) with
    Sync I/O interface(s) and
    ISDN interface

    Up to 2 CUs
    Sync I/O interface required for operation with VCU

    PLT RFU Unit and high power attenuator(s)

    One high power attenuator per MES

    MPLT software

    mini-M/M4 Physical Layer Tester

    NCS/LES emulator software

    Primary (single CU)
    Remote (for second CU)

    Voice Codec Unit (VCU)

    AMBE codec with 2W or 4W interface

    Supported Scenarios

    Terminal types

    Fleet 33/55/77

    Call types

    mini-M voice
    (4.8 kbps AMBE)
    M4 / M4 Aeronautical voice
    (64 kbps PCM)
    M4 / M4 Aeronautical audio
    (64 kbps PCM, 3.1 kHz audio)
    M4 / M4 Aeronautical data
    (64 kbps UDI)

    Maximum number of CUs


    Maximum number of calls (single hop)

    Single CU: 2
    Dual CU: 6

    Maximum number of calls (dual hop)

    Single CU: 1
    Dual CU: 3

    Maximum number of 64 kbps ISDN calls

    Single CU: 2
    Dual CU: 4

    Call Routing


    Initiated by MES or equipment attached to MES; dialed number determines terminating interface


    ISDN: Initiated by ISDN equipment; dialed # determines MES
    mini-M voice: Initiated via GUI; dialed number determines MES


    Initiated by MES or equipment attached to MES; dialed number determines terminating MES

    Example Configurable Parameters

    Ocean region

    Bulletin board
    Operating frequencies/power

    Authorized MESs

    Forward/return IDs
    Signalling (standard or NG)
    Terminal type (e.g., aeronautical)

    Dialing strings for fixed-terminated calls

    VCU termination
    ISDN termination

    Dialing strings for mobile-terminated calls

    Call type / Terminal id

  • Mini-M/M4 NCS-LES Data Sheet

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