V.90 Software

VOCAL's V.90 software library is fully compliant with the ITU V.90 Recommendation and highly optimized for most DSP architectures. There are 22 modulation rates in range of 28000 bps to 56000 bps, in increments of 1.333 kbps. VOCAL's V.90 software uses state-of-the-art line probing analysis to automatically determine maximum channel capacity. It also support MSE fallback/fallforward threshold control to adjust the tradeoff between higher data channel rates and symbol error rates. Rigorously tested with commercial standalone servers and client modems, based on the ITU and TIA recommendations ITU V.56bis, V.56ter, TIA TSB37A and TSB38.

Depending upon V.90 configuration selected, the line interface may be an analog front end (codec and DAA) or a digital interface such as T1/E1, switched 56 and ISDN. The upper end of this software can provide PPP, V.14, HDLC or direct binary framing layers. Higher data protocol layers, V.42 (including MNP 2-4), V.44, V.42bis and MNP5 are options as well.

This modulation family can be combined with other data modulations (V.92, V.34, V.32bis/V.32, and V.22bis/ V.22/V.23/V.21). V.8/V.8bis startup procedures can be used. All data modulation software is fully compatible with VOCAL’s facsimile, telephony, speech coder and multimedia systems.

Terminology

  • V.90 (Determined February 1998) refers to procedures between a "digital modem" and an "analog modem". The analog modem, which may be connected to the PSTN through either an analog or digital interface, transmits V.34 signals and receives G.711 PCM signals. The digital modem, which is connected to the PSTN through a digital interface, transmits G.711 PCM signals and receives V.34 signals.
  • V.90 (Determined February 1998) refers to analog/digital configurations. Future ITU recommendations or extensions to V.90) may refer to digital/digital configurations and/or PCM transmit and receive for an analog/digital configuration.

Features

  • Modem MIB Support (RFC 1696).
  • Specifies 22 modulation rates in range of 28000 bps to 56000 bps, in increments of 1.333 kbps. (Administration requirements may restrict maximum rates/power allowed).
  • Multi-tasking environment compatible.

Configuration

  • As per terminology above, three V.90 system configurations are relevant: systems that implement an analog modem only, systems that implement a digital modem only, and systems in which the modem can take on the role of either an analog or digital modem.
  • Analog modem DAA interface using linear codec at 16.0 kHz sample rate.
  • Digital modem direct interface to 8.0 kHz PCM data stream (A-law or m-law).
  • PPP (RFC1662), V.14, HDLC and direct binary framing layers available.
  • North American and International Dialing/Telephony functions available.
  • Data protocol layer (V.42/MNP2-4/V.44/V.42bis/MNP5) available.
  • System can be combined with V.110 rate adaptation software.
  • System can be combined with other modulations (V.92, V.34, V.32bis, et al.) and automode procedures(V.8bis, V.8 and PN-2330).
  • Data/Facsimile/Voice Distinction upon startup available. Complete facsimile systems, modulations (V.34, V.17 et al.) and protocols (T.30), and speech coders available.

Figure 1 shows VOCAL's V.90 block diagram.

VOCAL's V.90 block diagram
Figure 1 V.90 Block Diagram


Block Diagram

ITU Recommendation V.90