WO1999046727A1

WO1999046727A1 - Portable telephone accessory for temporary storage of fax and data

Info

Publication number: WO1999046727A1
Application number: PCT/US1999/005292
Authority: WO
Inventors: Randall G. Bright
Original assignee: Ericsson Inc.
Priority date: 1998-03-11
Filing date: 1999-03-11
Publication date: 1999-09-16
Also published as: AU3078699A

Abstract

A plug-in module for a portable telephone, capable of storing data, fax, and voice messages onto flash memory. The module is powered by the host telephone, and interfaced using serial lines. The serial signals are relayed to external supplemental devices using an RS-232 interface.

Description

PORTABLE TELEPHONE ACCESSORY FOR TEMPORARY STORAGE OF FAX AND DATA

Background of the Invention

The present disclosure relates to Digital Advanced Mobile Phone Service (DAMPS), and more particularly to the application of detachable nonvolatile memory to digital cellular telecommunication devices.

The first generation of cellular technology uses an analog modulation process to convey information from point to point. The system design known as Advanced Mobile Phone Service or AMPS employs analog frequency modulation for speech transmissions and frequency shift keying for signaling. The concept assigns each call a pair of unique frequencies within a limited geographic area. Unlike open platform protocols, each cellular call is serviced by a semi-private two channel line. The first channel is dedicated to broadcast transmissions and the second channel is dedicated to receiving transmissions.

To increase accessibility, interoperability, and functionality, the conventional analog infrastructure is gradually being replaced by digital technology. Digital telecommunication offers several advantages over conventional analog systems. Ease of processing, ease of multiplexing, ease of encryption processes, high noise immunity, improved spectral efficiency, improved data transmissions, enhanced speech quality, and an ability to support new functionality such as integrated paging, messaging services, and caller identification are a few of the advantages digital telecommunication offers over conventional analog architecture.

The first generation of digital protocol approved by the FCC in 1990 was IS 54 or Time-Division Multiple Access (TDMA). TDMA is a dual mode analog and digital platform that accommodates digital and analog protocols. TDMA triples the capacity of current analog channels by deriving three separate digital channels or time slots from each analog channel. With the advent of IS 136, the digital control channel offers enhanced services such as slotted paging, caller, number, and name identification, point-to-point text messaging services, and integrated paging which require application software residing in memory. Code Division Multiple-Access (CDMA) is another standard of digital wireless communications. The concept behind CDMA is to digitally modulate data on a given common frequency assigned a complex pseudo random code. The process only deciphers transmissions by extracting data assigned to a given code, and hence, is an efficient use of available bandwidth. Because the key to performance of such system in detection of a signal is the signal coding, this type of cellular protocol requires complex processing supported by sufficient memory. According to conventional practice, cellular memory is burdened by the task of storing all the application software of the cellular system. Unfortunately, the underlying complexity of CDMA and TDMA protocols limit the functionality of cellular systems as cellular features are critically dependent on size and efficiency of cellular memory.

Progress in the cellular industry has been guided by the principal of better performance at a minimum cost. Given that additional memory is an effective way of increasing cellular performance, there exists a need to provide a reliable expansion card capable of providing real-time performance and fast read/write access at a low system cost. With continued reliance on permanent resident nonvolatile memory, current cellular technology is limited to the manufactured state of the art, and a point of diminishing return is continuously reached as innovation exceeds memory capacity.

The escalating requirements of digital cellular technology and services including fax, integrated paging, messaging, data transmission, caller alert, require a reliable inexpensive portable memory. The memory must be physically compatible with the decreasing size of hand-held portable units, easy to install, consume little energy, and offer long-term compatibility to ever changing digital standards.

SUMMARY OF THE INVENTION

A memory device for providing fast access, nonvolatility, and low power consumption memory in a TDMA or CDMA-based telecommunication system is disclosed. The memory device combines resident memory with the high performance of a dedicated detachable block of nonvolatile memory. The memory device is comprised of two interface buses capable of supporting a read/write architecture. The memory hierarchy connected to one interface bus is modeled as a non-interleaved functional unit having an internally managed nonvolatile memory operative to store a plurality of embedded algorithms and a modular memory cartridge. The modular memory cartridge includes a second interface bus linked to a microcontroller having at least one serial data driver built therein. The modular memory cartridge further includes a block of low-voltage nonvolatile memory. The memory device may also be virtual memory comprising a block of resident memory and a portable nonvolatile flash memory card.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a conventional digital cellular telephone having a permanent resident nonvolatile memory.

FIG. 2 is a block diagram of a first embodiment of a modular memory cartridge.

FIG. 3 depicts the interface of the modular memory cartridge to a digital cellular telephone in accordance with FIG. 2.

FIG. 4 depicts a second embodiment of the present invention.

FIG. 5 depicts the interface of the embodiment depicted in FIG. 4 with a digital cellular telephone.

FIG. 6 depicts a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS The present disclosure departs from conventional digital cellular technology by increasing the design functionality of digital cellular devices. The present disclosure enables the digital cellular user to adapt to a variety of cellular platforms that achieve improved reliability, higher operating speeds, and improved performance through a memory hierarchy modeled as a non-interleaved functional unit.

Digital cellular technology conventionally relied on a stand-alone fully integrated cellular telephones as illustrated in FIG. 1 , while avoiding the use of modular assemblies. Cellular technology is static sensitive, and therefore, a pin or socket misalignment which may occur in modular assembly can adversely affect the performance of a digital cellular telephone or worse result in its catastrophic failure. Moreover, due to the typical large sizes of external memories, smaller designs of digital cellular telephones, and focus on low-power electronic design, ancillary memory devices were considered incompatible with existing digital cellular design strategy.

In an embodiment of the present invention, a memory cartridge is fully enclosed within a nonconductive insulative sheath to protect against electronic static discharge (ESD). In a preferred aspect of this embodiment, a digital cellular circuit which includes a digital transmitter, a digital receiver, and a digital logic circuit interfaced to the memory cartridge share a common power and ground plane further reducing the possibility of static induced damage. In another preferred aspect of this embodiment, a system bus connector provides further isolation between the digital cellular circuit, the memory cartridge, and a plurality of peripheral electronic devices the memory cartridge may drive. Thus, the use of the system bus connector between the ancillary memory and the cellular circuitry also affords isolation between the digital cellular technology and a plurality of peripheral devices. In one embodiment of the invention, a nonvolatile flash memory card having between a two and eight megabyte density was enclosed in a thirty-eight by thirty-three millimeter package which is fully compatible with the smaller designs of digital cellular telephones.

An embodiment is illustrated in FIG. 2, wherein for simplicity, depicted elements are not necessarily drawn to scale and alike and similar elements may be designated by the same reference numerals through several views. As shown in FIG. 2, a memory cartridge 200 has a system bus connector 208, an RS232 line driver 212, an RJ-11 connector 214, a microcontroller 216, and a block of nonvolatile memory 222. Accordingly, the system bus connector 208 provides a serial interface 226 between a digital cellular telephone 224 serial port 202 and the micro-controller 216 serial port 210 to support a read/write architecture. While actual serial communication can occur in several ways, in this embodiment the microcontroller 216 drives and receives serial communication through a built in serial port chip or UART. Such serial communication may be based on an AT command structure. Besides providing a means for facilitating communication between the digital cellular telephone 224 and the microcontroller 216, the system bus connector 208 provides isolation between a power 204 and a ground 206 bus that derives power from a portable power source connected to the digital cellular telephone 224.

Operation of the memory cartridge 200 is controlled by the microcontroller 216. When the microcontroller 216 is booted up, it looks for memory. The nonvolatile block of memory 222 may be accessed by the microcontroller 216 by means of a parallel bus comprised of an address bus 218 and a data bus 220. The RS232 line driver 212 coupled to the RJ-11 connector 214 provides bipolar data and control signals of substantial drive capability to a plurality of peripheral devices. In this embodiment, a low voltage-flash memory block having less than one-hundred and twenty nanosecond access time, distributing data in a sequential file format, and compatible with a single power source was implemented. A dual driver positive receiver RS 232 integrated circuit may be used in this embodiment because it conveniently has an on-chip flying-capacitor voltage doubler and inverter and therefore is capable of running from a single positive supply.

As illustrated in FIG. 3, the memory module 200 is freely attachable and removable from the digital cellular telephone 224. The memory module 200 easily snaps onto the lower end of the digital cellular telephone 224 by the engagement of a plurality of locking tabs 306. The locking tabs 306 are flexibly connected to the memory module 200 which is enclosed within a nonconductive insulative sheath 304 hermetically sealed to repel contamination and cushion shock trauma. The performance characteristics of the memory module may be further improved by the use of elastomer connectors on the memory module 200 and the digital cellular telephone 224 to minimizes pin and socket misalignment that may occur in modular cellular assembly.

The use of ancillary memory expands the current functionality of digital cellular telephones by providing storage capacity that enables over the air reprogramming, point-to-point messaging, integrated answering functions, and data logging for later recovery and analysis.

The embodiment of FIGS. 4 and 5 is similar to that depicted in FIGS. 2 and 3 as it comprises a block of nonvolatile memory. However, the conditioning circuitry of the previous embodiment is integrated within the digital cellular telephone 224 having a portable power source and therefore is not needed in a nonvolatile miniature memory card 400. Thus, FIGS. 4 and 5 constitute a further improvement of the embodiment shown in FIG. 2, by decreasing the number of components of the ancillary memory thereby reducing its size without affecting its interchangability. In this embodiment, the nonvolatile miniature memory card 400 is a block of flash- memory seamlessly integrated with a block of resident cellular memory which in association is referred to as a virtual memory. In another embodiment, the miniature memory card is interfaced to a controller that monitors the integrity of the read/write cycles. By sequentially writing to a given memory address and then reading its content, the controller may detect a memory failure and notify the digital cellular circuitry to prevent further storage at that address.

As illustrated in FIGS. 4 and 5, the nonvolatile miniature memory card 400 is attachable and removable from the digital cellular telephone 224. The nonvolatile miniature memory card 400 easily snaps into the back of the digital cellular telephone 224 by the engagement of a plurality of locking tabs 404. The locking tabs 404 are flexibly connected to the nonvolatile miniature memory card 400 which is enclosed within a nonconductive insulative sheath 406.

The illustrated embodiments employ software that automatically configure the ancillary memory and limit the number of write cycles of each memory address. When a user attaches a memory expansion card or module, the memory is automatically operational without user support. The embodiments utilize a variety of Plug and Play technology wherein each module is uniquely identified, capable of stating the services it provides, capable of identifying the software driver that supports it, and allows the operating software to configure its use. A digital cellular telephone user simply attaches the ancillary memory device and it begins to play. Besides providing a common platform that enables digital cellular users to support new digital services, the digital cellular Plug and Play memory expansion device provides the user with greater mobility. A user may remove the portable memory device from the digital cellular telephone without interrupting a digital cellular transmission and dock the portable memory without losing memory content or having to configure the memory device to the docking station's operating software. A docking station could then retrieve the data for further processing or download additional data to be used or transmitted by the digital cellular telephone 224. Accordingly, a docking station is any device that supports Plug and Play technology having a serial data communication port, like a computer.

The illustrated embodiments can also employ a visual display. FIG. 6 shows an LCD display 232 having a display driver 212 serially connected 228 to the microcontroller 216. The visual display may be mounted onto the memory cartridge 200 as shown in FIG. 6 or directly onto the nonvolatile miniature memory card 400. In the embodiment depicted in FIG. 6, when the memory module 200 is directly connected to the cellular telephone 224, the cellular telephone keypad 308 may function as a means for scanning the contents of the memory module 200 on the LCD display 232. In another embodiment, the visual display may be coupled directly to a portable scanning device and a portable power source so that the visual display is part of a fully functional portable memory module when it is detached from the digital cellular telephone 224. In a further embodiment, the visual display is an LED display. Various embodiments may also employ hybrid electronic displays.

The concepts and processes previously illustrated may be implemented through software and logic circuitry. The aforementioned embodiments were employed using conventional circuitry and software including an RS232 serial data driver, an Intel Series 100 Flash Memory Miniature Card, a FTL Flash File System, and software adapted from a Common Flash Interface Specification and a Plug and Play Design Specification. Although the disclosure is not limited to a block of flash memory as a battery backed SRAM or an EEPROM may also be used, the use of portable flash memory provides fast access times, high endurance cycles, low energy consumption, single power supply operation, direct executions meaning code and data may be read directly from memory, and a smaller size in comparison to conventional storage devices. The disclosed embodiments enjoy utility in any digital cellular telephone application.

Variations and modifications of the embodiments disclosed herein may be made without departing from scope and spirit of the invention. The aforementioned description is intended to be illustrative rather than limiting and it is understood that the scope of the invention is set forth by the following claims.

Claims

I CLAIM:

1. A digital cellular telephone system for storing incoming cellular voice, fax, and data transmissions, wherein said digital cellular system comprises: a first interface bus capable of supporting a read/write architecture; a memory hierarchy connected to said first interface bus, wherein said memory is modeled as a non-interleaved functional unit comprising: an internally managed resident nonvolatile memory operative to store a plurality of embedded algorithms of said digital cellular telephone; and a modular memory cartridge structured to include: a second interface bus having address lines, data lines, and control lines; a microcontroller coupled with said second interface bus and having at least one serial data driver built therein; a block of low-voltage nonvolatile memory conductively coupled to second interface bus.

2. The digital cellular system as defined in claim 1 , wherein said nonvolatile memory residing in said modular memory cartridge is a flash memory and wherein said memory module is enclosed in a nonconductive insulative sheath.

3. The digital cellular system as defined in claim 1 , wherein said microcontroller is operative to distribute said data in a sequential file format.

4. The digital cellular system as defined in claim 1 , wherein said embedded algorithms are reconfigurable operating software responsive to said digital cellular transmissions.

5. The digital cellular system as defined in claim 1 further comprising an expansion bus interface operatively coupled between said first interface bus and said microcontroller.

6. The digital cellular system as defined in claim 5 further comprising an RS232 interface operatively coupled to said expansion bus interface and said microcontroller, said RS232 interface operative to distribute data to one or more electronic peripheral devices.

7. A smart digital cellular apparatus capable of temporarily storing fax and data transmissions, comprising: a digital cellular circuit having a digital transmitter, a digital receiver, and a digital logic circuit, said digital cellular circuit digitally linked to one or more digital switching stations; a portable power source operably coupled to provide power to said digital cellular circuit; a virtual memory device seamlessly integrated with said digital cellular circuit and drawing power from said power source, comprising: a resident nonvolatile memory device responsive to receiving and transmitting said digital cellular transmissions; and a transportable nonvolatile miniature memory card responsive to user programmable features.

8. The smart digital cellular apparatus of claim 7, wherein said nonvolatile memory is a mask-programmed read only memory.

9. The smart digital cellular apparatus of claim 7, wherein said nonvolatile miniature memory card comprises a block of flash memory enclosed within a nonconductive insulative sheath.

10. The smart digital cellular apparatus of claim 7, wherein said miniature memory card is interfaced to a controller constructed to monitor the integrity of the programmable and erasure cycles of said memory, wherein said controller is associated with an authentication device to prevent the reprogramming of failed memory sectors and capable of communicating an address of said failed memory sectors to said digital cellular circuit.

11. The smart digital cellular apparatus of claim 7, wherein said nonvolatile memory device is embedded with algorithms responsive to over the air reprogramming in a digital cellular format including at least one of a plurality of digital cellular formats including a Time-Division Multiple Access format and a Code- Division Multiple Access format.

12. The smart digital cellular apparatus of claim 7 further including an answering device interfaced to said miniature memory card for recording an outgoing greeting and storing incoming messages from a digital cellular transmission in a compressed file format in said transportable nonvolatile miniature memory card.

13. The smart digital cellular apparatus of claim 7, wherein said miniature memory card is a flash miniature memory card easily removable from said digital cellular circuit and interchangeable with a plurality of pre-programmed miniature memory cards capable of reconfiguring the functionality of said digital circuit.

14. The smart digital cellular apparatus of claim 13, wherein said programmable features support a pre-programmed communication service configurable to the user of said smart cellular apparatus and reconfigurable by interchanging said preprogrammed miniature memory card with a plurality of said pre-programmed miniature memory card.

15. A method of interfacing a multi-level hierarchy of nonvolatile memory in a Digital Advanced Mobile Phone Service, comprising the steps of: providing a digital cellular telephone having a digital logic circuit, a plurality of digital memory, an interface bus, and a portable power source; electrically coupling said digital logic circuit to said power source; operably coupling said interface bus to said digital logic circuit; interfacing a fixed block of resident nonvolatile memory to said interface bus and said power source, said fixed block of resident nonvolatile memory operative to store the operating system of said digital cellular telephone; and

10 interfacing a detachable block of nonvolatile memory to said interface bus and said power source.

16. The method of claim 15, wherein said detachable block of nonvolatile memory is a Plug and Play flash memory card configured to said Digital Advanced Mobile Phone Service for storing a plurality of user programmable features.

17. The method of claim 15, wherein said nonvolatile memory are flash memory that draw power from said power source only during read/write cycles.

18. The method of claim 15 further providing a display means, wherein said detachable block of nonvolatile memory is interfaced to a visual display that provides means for displaying the contents of said nonvolatile memory.

19. The method of claim 15 further providing a microcontroller having at least one serial data driver built therein operably coupled between said fixed block of nonvolatile memory and said detachable block of nonvolatile memory for managing data transfers between said fixed memory and said detachable memory.

20. The method of claim 19, wherein at least one of said serial data interfaces is an RS232 interface operative to distribute data to one or more electronic peripheral devices.

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