The MUSYCC card is a high-throughput communications controller
for synchronous, link-layer applications that multiplexes and de-multiplexes
up to 128 data channels. Each channel can be configured to support HDLC (LAPD,
Frame Relay), Transparent, or SS7 applications.
The card operates at the Layer 2 (the data link protocol level)
reference of the International Organization for Standardization (ISO) model.
Each channel has a programmable bit rate from 8 up to 2048 Kbps. The basic
card connects to the external world by means of a MVIP standard interface.
An extension board allows using the card also with the SCSA bus.
The host interface is compatible with the PCI local bus that operates at 33
MHz with 5 V according to the PCI Local Bus Specification (Revision 2.1, June
1, 1995). The host interface can act as PCI master and PCI slave, and contains
the configuration space and the internal registers. When the PCI controller
needs access shared memory, it masters the PCI bus and completes the memory
cycles without external intervention. The card provides two functions on
the PCI bus, the first one for accessing the HDLC controller, the second one
for the MVIP and the SCSA controllers.
This device provides a channelized serial interface that consists of 4 serial
ports connected to the MVIP (or SCSA) controller, a set of bit level processors,
a direct memory access controller, and a shared interrupt controller. Channelized
mode refers to a data bit stream segmented into frames. Each frame consists
of a series of 8-bit time slots. Typically, each time slot recurs every 125
us at an 8 kHz rate. The HDLC controller supports subchanneling, that is the
capability of handling a number of bit per frame lower than 8 (8/16/32 Kbps).
Conversely up to 32 timeslots can be mapped on a single channel resulting
in a rate of 2048 Kbps. The card interfaces with a system host using a set
of data structures located in a shared memory region. It also contains a set
of internal registers which the host can configure and take control of. The
card supports a memory model whereby data is continually moved into and out
of a linked list of data buffers in shared memory space for each active channel.
A system topology, in which a host and the card both have access to shared
memory space for data control and data flow, is assumed. The data structures
are defined in a way that the control structures and the data structures
may or may not reside in the same physical memory and may or may not be contiguous.
The host allocates and deallocates the required memory space as well as the
size and number of data buffers within that space for each of the active
data channels with common list processing structures. This architecture allows
data transmission between buffer memory and the serial interfaces with minimum
intervention by the host processor that can be used for managing the higher
layers of the protocol stack.
The MVIP (Multi Vendor Integration Protocol) is the most widely used standard
for the evolving field of computer telephony. MVIP focuses on inter-operation
of components from different vendors and upon software portability between
hardware components and between platforms. This standard provides:
- A multiplexed digital telephony bus with 512 x 64 Kbps capacity
(256 full-duplex paths)
- A distributed circuit-switching capability (inside the computer and under
- A sophisticated digital clocks architecture
Detailed information are available at: http://www.mvip.org
The MVIP controller can switch up to 128 time slots (64k bit/s) from/to
the MVIP to the serial lines towards the HDLC controller. It also provides
clock synchronisation by a digital phase locked loop circuitry, which provides
timing and synchronisation signals for all the devices on the card.
An extension board is available to allow connecting the MUSYCC card to the
SCSA (Signal Computing System Architecture) bus, in order to provide similar
functions but with a different type and location of the connector.
Software & Drivers
Drivers are available for many operating systems. Prisma Engineering can also
provide custom versions of them on the basis of specific needs.
MUSYCC board brochure