Telscale SS7 card

Scope of technology


Isup to SIP GW

BSC for low-cost 2.5G BTS




Telscale SS7 card is a small DSP-based computer, designed to be used with OpenSigtran software. It can be ether plugged inside a server or just powered with +5V DC.

Telscale card runs uClinux, has 2 synchronous TDM interfaces (E1 or T1) and 2 Ethernet ones.

The card is capable of acting as ether a signaling gateway or a probe.

Depending on the volumes, Telscale SS7 card can be ordered in another form-factors.

Card use cases

1. Telscale SS7 card populated with virtual Signaling Gateways

When used as a set of Signaling Gateways, a card is connected to PLMN via a couple of G.703 E1 or T1 interfaces, which can be populated with 64k (low speed) or 2M (high speed) signaling links.

The multiplexing sublayer distributes time slots with signaling between various SS7 stack instances that are runing inside a card as independent uClinux applications. Initial version of M3UA stack can be found here.

2. Telscale SS7 card as a Probe

Card is capable of monitoring 2 G.703 E1 or T1 interfaces and can be assumed as a cost-effective probe for various purposes.

It can be a part of SS7 monitoring/fraud detection/welcome-sms etc solution or can convert a PC with Wireshark into protocol analyzer, providing traces like USSD payload test.

Telscale SS7 card SGW specifications

As Telscale SS7 card is a stand-alone computer that interfaces the World via IP,

  • there are no limitations to host OS
  • multiple application servers can share card's resources
  • no drivers are required at the host side

    Parameter Tested Expected Comments
    2 x G.703
    PCM interfaces
    E1, 120 Ohm
    with or w/o CRC4
    T1, 100 Ohm
    D4 or ESF framing
    Line coding and framing is implemented inside Xilinx FPGA.
    E1 suite is well tested, several hundreds of interfaces deployed.
    T1 interface options are implemented and tested in lab, while there were no customers yet
    Number of SS7 links,
    LS (64k)
    HS (2M)

    24 low speed
    1 high speed

    62 low speed
    2 high speed
  • Initial MTP2 implementation is inherited from the previous fixed-point DSP solution and is completely software one It costs about 1.5% of 400MHz DSP per SS7 time slot, while moving bit-stuffing into FPGA eliminates it
  • A character-style device driver interfaces G.703 samples. Re-writing it as MMAP one will save about 5% DSP resources per PCM line
  • Sigtran M3UA M3UA/SCTP
    SCTP multi-homing
    M3UA Routing Context
  • When working in tandem with Mobicents jSS7, maximum configuration options were intentionally moved to java side
  • M3UA/TCP is useful when an application server runs under MS Windows, which does not natively support SCTP
  • Media Resources
  • G.711 payload
  • DTMF
  • echo
  • M2UA or M2PA adaptation layers will be implemented as soon as requested.