Compaq 850 manual Functional Description, Dsp Daa

Appendix F Compaq/Lucent V.90 56K PCI Modem

F.2 FUNCTIONAL DESCRIPTION

The Compaq/Lucent V.90 56K PCI modem provides data communication over a standard telephone network at transfer rates of up to 56 kilobits per second. The modem also supports facsimile (fax) transfers at up to 14.4 kilobits per second. Auto-detection of operating speed and compression mode is also provided. This modem is of the “controllerless” type, meaning that while the UART, DSP and DAA functions (Figure F-2) are provided by hardware the operational functions are largely handled by the modem driver. The modem driver is automatically loaded upon modem activity and automatically unloaded when the modem activity ceases.

PCI

Card Bus

PCI

16550

DSP

DAA

TX Data

RJ-11

Connector

Edge Connector

I/F

UART

Circuitry

RX Data

Figure F-2.Compaq/Lucent V.90 56K PCI Modem Block diagram

The Compaq/Lucent V.90 56K PCI Modem includes the following key features:

♦ITU-T V.90 56 Kbs and K56Flex support w/auto-negotiation of mode

♦14400 bps send/receive fax support

♦ITU-T V.42 error correction (LAPM and MNP)

♦V.42bis and MNP Class 5 data compression

♦TIA/EIA 602 standard AT comment set

♦115.2 kbps UART speed

♦PCI 2.2 compliant

♦PC99 compliant

♦APM, ACPI power management support

♦Windows 95, 98, NT4.0 support

Modem operation begins when a program in a virtual machine (VM) attempts to access the com port designated for the modem’s 16550 UART. A callback procedure is initiated, which loads the driver that takes over the trapping of the UART’s I/O ports. A background timer is started that checks for transmit empty / receiver ready states or any other interrupt condition. The com port for the modem remains open until the DOS VM is terminated. The driver will then unload itself and the com port will be released.

F-2Compaq Personal Computers

Original - December 2000