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Appendix F Compaq/Lucent V.90 56K PCI Modem
Compaq Personal Computers
Original - December 2000
F-2
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.
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.
DAA
Circuitry
DSP
PCI
Bus
Card
Edge
Connector
PCI
I/F
16550
UART
RJ-11
Connector
TX Data
RX Data