TeleSoft International provides  QSIG source code software and QSIG device drivers to accelerate development and conformance testing of your QSIG product. TeleSoft's software QSIG protocol stack provides the fastest path to market-ready QSIG products for manufacturers worldwide.  QSIG is a variant of ISDN, and is sometimes called PSS1 (Private Signaling System 1), and is sometimes incorrectly referred to as PSS-1,  PDSS1, or P-DSS1.  The QSIG source code library is sometimes called a "QSIG stack" or "QSIG signaling stack".

The TsLink3 ISDN software development toolkit is available in source code and is architected for applications, both embedded and host-based, in which performance and code size are important.

The TeleSoft ISDN SDK has available interfaces to several standard preemptive and non-preemptive real-time operating systems and non-real time operating systems, including ATMOS, Linux, MQX, Nucleus Plus, OSE, pSOS, TsRITE*, VRTX, and VxWorks 

If a customer selects a different OS than one from the list above, one of the pre-ported OS interfaces can be used as a template to rapidly develop a new OS interface. TsLink3 customers have leveraged the OS-independent architecture to port to other operating systems including Solaris, Windows, and Proprietary operating systems

Integrated Systems Digital Network (ISDN) is a term that encompasses a large number of protocols, including Q.921/Q.931 Narrow-band ISDN (N-ISDN), Q.2931 Broadband ISDN (B-ISDN), Q.922/Q.933 Frame Relay and other protocols.  Usually when you hear ISDN, it means the N-ISDN set of protocols (e.g. Q.921, Q.931.)  QSIG is a type of ISDN.

Narrowband ISDN (N-ISDN) also two major Physical interfaces--the two B channel Basic Rate Interface (BRI) and the 23, 24 or 30 channel Primary Rate Interface (PRI).  T1 lines may be channelized into 24 DS0 channels, one of which is used for the D channel (the signaling channel).    TeleSoft provides software that implements a QSIG protocol stack that supports both Network and User sides of QSIG and is available for both the Basic Rate Interface (2B+D) and the Primary Rate Interface (23B+D or 30B+D).   Most commonly, QSIG is supplied over an E1 as a 30B+D service.

The QSIG protocol stack is used for PBX to PBX communication, and is considered a "symmetrical" ISDN stack, that is, there is no User vs. Network side.  There is, however, an "A" and a "B" side (sometimes called a "master" and "slave" side) for the purpose of glare resolution, but this difference is much smaller than the Network and User side difference of Q.931.  Normally, any equipment that supports QSIG has the "A" or "B" side option configurable at run time, on a line-by-line basis.  TeleSoft supplies QSIG source code.

TeleSoft's QSIG source code stacks is amongst the most proven and feature-rich available today. In addition to PSS1, AutoSPID, Autoswitch Detection, NFAS, and D-Channel Backup, a wide range of conformance tested worldwide switch variants is available. Full NT and TE side support is included. Q.921 LAPD and Q.931 LAPB can be licensed either individually or as an integrated stack

TeleSoft licenses well-proven source code for AutoSPID, Autoswitch Detection, NFAS, and D-Channel Backup in addition to DSS1 and other switch variants used worldwide.  TeleSoft also supplies Voice Supplementary Services, also referred to as Q.932. 

The TsLink3 ISDN software development toolkit is available in source code and is architected for applications, both embedded and host-based, in which performance and code size are important.

The TeleSoft ISDN SDK has available interfaces to several standard preemptive and non-preemptive real-time operating systems and non-real time operating systems, including ATMOS, Linux, MQX, Nucleus Plus, OSE, pSOS, TsRITE*, VRTX, and VxWorks 

If a customer selects a different OS than one from the list above, one of the pre-ported OS interfaces can be used as a template to rapidly develop a new OS interface. TsLink3 customers have leveraged the OS-independent architecture to port to other operating systems including Solaris, Windows, and Proprietary operating systems

* TsRITE is a TsLink3 product, and is a compact, low-overhead RTOS customized for protocol and B-channel data requirements. It is royalty-free.

TeleSoft International is the original developer of the TsLink3 range of high performance WAN protocols including ISDN BRI and PRI, QSIG, CAS E1 R2, T1 RBS, AO/DI, ML-PPP, Frame Relay, X.25, and also a range of hardware reference designs. TsLink3 protocol source code is exceedingly well engineered - tightly coded for performance and compact footprint, with a quality that delivers rock-solid stability.

TeleSoft's foundations go back to 1986 when the first ISDN stack was released. Since then TeleSoft's protocols have been proven in use by more than 200 customers worldwide. World leaders, including AT&T, Cisco, D-Link, Digital Equipment, Fujitsu, IBM, Lucent, Matsushita, Multi-Tech, NTT, Polycom, and Vertical Networks have all used the source code for  TeleSoft's proven protocol software.

Manufacturers license the source code for TeleSoft's proven Protocol Stacks and Reference Designs to get their products to market faster with minimized technical risk and development costs. TeleSoft focuses on developing the software and hardware so that you can focus on manufacturing and shipping your product.