Intel 536EX manual 1.2V.90/V.92 and V.34 Data Modes, Intel Confidential, Introduction

Introduction

When the controllerless chipsets are used with MS-DOS* applications, however, a UART emulation is required. Intel provides an additional driver called Intelsdb.VxD, which includes a UART emulation. Please refer to Section 9.1, “UART Emulation in the Controllerless Modem” on page 92 for an explanation of the 536EX UART emulation. The Intelsdb.VxD driver interacts directly with the VCOMM.VxD driver using the Win16 and Win32 Communication APIs.

Figure 2. VxD Mini Port Driver Block Diagram

NON-SYSTEM
VIRTUAL MACHINE	SYSTEM VIRTUAL MACHINE
MS-DOS SHELL APPLICATION
OR DRIVER
MS-DOS	WINDOWS
APPLICATION	APPLICATION
	TAPI	Win 16
	Unimodem	COMM.DRV
Intelsdb.VXD	VCOMM.VXD
	HaM Port Driver
	Interrupt Services
	Chipset Hardware

1.2V.90/V.92 and V.34 Data Modes

The 536EX chipset defaults to the V.90 or V.92 mode depending on the driver version. The V.90/ V.92 mode allows receive data rates of up to 56,000 kbps over the PSTN (public switched telephone network) only in connections with equipment-compatible ISPs (Internet Service Providers); however, FCC regulations limit receive speeds to 53,333 kbps due to excessive power demands at higher speeds. In modem-to-modem connections, V.90/V.92 mode falls back to V.34 mode in both the transmit and receive directions. The chipsets implement all data rates and modulation schemes for ITU-T (International Telecommunications Union-Telecommunications) standards V.34, V.32 bis, V.32, V.22 bis, V.22, V.21, Bell 212A, and Bell 103.

536EX Chipset Developer’s Manual 9

Intel Confidential