AccessRunner ADSL-USB Modem Device Set Data Sheet
User selection of WAN or LAN mode can be done manually via the provided control panel. However, auto-configuration is
supported with the provided installation wizard, so that the protocol mode is selected properly without user intervention.
2.2.2 Host Software
The host software NDIS miniport driver provided implements the ATM Adaptation Layer 5 (AAL5), which is composed of two
sublayers: 1) the Segmentation and Reassembly (SAR) layer, and 2) the Convergence Sublayer (CS). The AAL5 protocol
provides virtual connections, which offer error detection, but not error correction, between end stations attached to the same
The SAR sublayer transmitter segments the higher layer information into a size suitable for the payload of the ATM cells of a
virtual connection. The receiver reassembles the contents of the cells of a virtual connection into data units to be delivered to
higher layers. During periods of no data transmission, the device set, and not the host software driver, performs idle cell
insertion and deletion, thus unloading this task from the host PC and unburdening the USB with unnecessary traffic.
The Convergence Sublayer performs message identification and clock recovery. Additionally, the CS of the AAL converts the
user service information coming from the upper layer into a protocol data unit (PDU), and also carry out the opposite process
at the receiver.
Unspecified Bit Rate (UBR) service is supported. It allows a connection to be established without specifying the bandwidth
expected from the connection. The network makes no guarantees for UBR service: it establishes the route but does not
commit bandwidth. UBR can be used for applications that have no delivery constraints and do their own error and flow
control. Examples of potential uses or UBR are e-mail and file transfer, as neither application has real-time characteristics.
2.2.3 Control Panel
A Windows Control Panel Applet is provided to monitor and control ADSL line and call activity, accumulate ADSL line and call
statistics, and identify the software and connection information. The control panel provides different levels of information: 1)
User, 2) Advanced User, 3) Developer. It is intended that only the User level information, which consists of basic connection
statistics such as line rate and connect status, is available to the end user. Other information available to the Advanced User
and Developer include Physical Layer Statistics, ATM Link Statistics, AAL Link Statistics, Protocol setup, and a logging
capability, which collects performance data and logs it to disk.
2.2.4 Installation Wizard
A Windows Installation Wizard is provided to ease the user’s provisioning of the ADSL service. The Wizard allows the user to
select a service provider allowing the associated setup profile to automatically ensure proper setup and installation of the
software drivers. The profiles, based on input from various ADSL service providers, are provided to facilitate deployment and
to minimize user involvement in provisioning ADSL service. A profile contains configuration information for physical layer
options, ATM layer parameters, AAL layer parameters, and TCP/IP layer parameters.
2.3 Device Description
2.3.1 P5200 UIC Description
The P5200 USB Interface Controller (UIC) is the bridge device between the CX11627 ADSL DMT Data Pump (ADDP) and the
host computer. It provides the control, interface, and data manipulation for the CX11627 ADDP, the CX20431 Analog Front
End (AFE), the CX20441 Line Driver (LD), and hybrid circuitry.
The P5200 has output ports for LED indicators and an interface to serial EEPROM for storing vendor specific descriptors. The
UIC conforms to the USB Specification Rev. 1.1 and supports full-speed (12 Mbps) USB device implementation.
The P5200 operates from +1.8V for core operation and +3.3V for interface circuit operation. The P5200 can operate with
+3.3V interface signals (VGG = +3.3V) or +5V interface signals (VGG = +5V).
The ARM Processor provides the controller and supervisory tasks of the ADSL-USB system. It moves data between the USB
port and the ADSL interface. Control code for the ARM is executed from external memory under control of the External
Memory Controller (EMC).
External Memory Controller
The External Memory Controller (EMC) provides a 16-bit interface to support up to 8 Mbytes of external memory. SDRAM or
SRAM is supported to maintain lowest cost of external memory. There can be 1 (16 bits wide) or 2 (8 bits wide) memories that
can reside on the EMC bus. This bus is not shared with any other functions so activity on this bus can be concurrent with
asynchronous and independent USB port or ADSL data transfers.