The Portfolio Main Unit has a 60-pin bus connector on its right-hand side for the connection of peripheral devices. The bus is electrically similar to the bus on an IBM PC in that all address and data signals are present as well as control signals and power, so that it can be used with a wide variety of additional devices. The bus interface is unique to the Portfolio and is used only to interface with specially designed Portfolio peripherals. However, two of the peripherals convert the proprietary Portfolio bus interface into the industry-standard Centronics parallel or RS-232C serial interfaces, permitting the attachment of many existing standard peripherals such as printers and modems, and providing for connection to other computers. The bus is documented in the Portfolio Technical Reference Guide that is available to registered Portfolio developers. Although there is only one bus connector on the Portfolio itself, more than one peripheral can be attached to the Portfolio by means of "daisy-chaining." Certain peripherals, currently only the Memory Expander Plus, have two bus connectors: one female connector on the left to connect to the Portfolio (or another peripheral) and a male connector on the right that can be used for the connection of additional peripherals. This kind of peripheral can be called a "Bus Extender Peripheral." Other peripherals, currently the Smart Parallel Interface and the Serial Interface, have only the left bus connector that attaches to the Portfolio or a Bus Extender Peripheral and no bus connector on the right. This kind of peripheral can be called a "Bus Terminator Peripheral." It must be the last peripheral that is physically connected, and only one such peripheral can be physically connected at a given time. A chain of up to three peripherals can extend horizontally to the right of the Portfolio in a "bar" formation, while the Portfolio is arranged on a flat working surface. Such a configuration is not practical for portable use. All peripherals take their power from the batteries or A.C. Adaptor in the Portfolio itself; they do not need their own batteries or separate A.C. Adaptors. Peripherals containing RAM must remain connected to Portfolio to retain the content of their memory, even when Portfolio is turned off. Since peripherals draw additional power from the main batteries, battery life is reduced. Battery life for continuous operation of the Portfolio alone is approximately 14 to 42 hours. For a system that also includes two Memory Expansion Modules and a Parallel or Serial Interface, battery life is reduced to approximately 8 hours. Actual battery life under typical operating conditions is significantly longer because of the automatic shut-off feature. It is important to note that under most conditions the A.C. Adapter would be used so that the actual length of time of your battery life is much longer than it may first appear. MEMORY EXPANDER PLUS, Model HPC-104 This peripheral contains 256 kilobytes (256K) of random access memory (RAM) that is used to extend the internal 128K RAM in the Main Unit. The basic Portfolio comes with 384K memory in the form of 256K ROM and 128K RAM. With the addition of the Memory Expander the Portfolio becomes a 640K system: 256K Internal ROM 128K Internal RAM 256K Expansion RAM 640K Total Memory The memory in the Memory Expander is contiguous with the 128K internal RAM, yielding a block of 384K RAM shared between the internal RAM disk (Drive C:) and the area of memory used for programs and data. A larger RAM disk can be used for more and/or larger user files and a larger program/data area can be used to load and run larger programs and work on larger datasets. The Memory Expander Plus contains a slot that accepts a Memory Card or a Program Card similar to the slot on the left end of the Portfolio Main Unit. The second card slot can be used for several purposes. For example, you can have both a Program Card containing an external application program and a Memory Card that contains files that the application program uses. You can also use both slots for Memory Cards as a quick way to "Diskcopy" the content of one Memory Card to another Memory Card. The Memory Expander is a "Bus Extender Peripheral." It contains a bus connector on the left to attach to Portfolio (or another peripheral) and a second bus connector on the right for the attachment of additional peripherals. Two Memory Expanders may be attached to Portfolio at the same time to further extend the internal RAM memory to 640K RAM for total memory of 896K: 256K Internal ROM 128K Internal RAM 256K Expansion Module #1 256K Expansion Module #2 896K Total Memory If two Memory Expanders are used, only one of additional card slots is active. The Memory Expander uses battery or A.C. Adaptor power from the Main Unit and reduces battery life somewhat. Memory contents are lost when it is disconnected from the Main Unit. SMART PARALLEL INTERFACE, Model HPC-101 This peripheral implements the industry-standard "Centronics" parallel interface. It can be used to attach the Portfolio to a variety of standard peripherals that have parallel interfaces, such as printers, that are available from a variety of manufacturers. It can also be used to connect to the parallel interface of IBM PC-compatible computers, providing a method of transferring programs and data files. The Portfolio contains an internal application program called "File Transfer" that uses the Smart Parallel Interface to upload or download files with another computer. You can use this facility plus the included File Transfer software for IBM PC compatible computers, for example, to download compatible MS-DOS software and run the software in the Portfolio. You can upload Portfolio Text Editor text files containing notes and import them into your PC word processing program for editing, formatting and printing. You can download compatible Lotus 1-2-3 spreadsheet templates created on the PC and use them in the built-in Worksheet program. Many similar applications are possible. The PC File Transfer software is supplied on both 5.25 inch and 3.5 inch floppy diskettes. For this application a standard RS-232C serial cable with a DB-25P male connector, completely wired, is needed. This cable, commonly used with serial rather than parallel interfaces, is available from most computer dealers. The internal application programs of the Portfolio contain several options that allow printing. Printed output can be directed by means of the built-in Setup program to a printer connected to the Smart Parallel Interface. The Smart Parallel Interface is a Bus Terminator Peripheral, with a Portfolio Bus Connector on the left and a Centronics-type parallel interface connector on the right. It must be the last peripheral on the bus and cannot be used with another Bus Terminator Peripheral. You will also need a standard IBM PC parallel printer cable to go between the Interface and the parallel interface connector on the other device. This peripheral takes its power from the batteries or A.C. Adaptor in the Main Unit and reduces battery life somewhat. SERIAL INTERFACE, Model HPC-102 This peripheral implements the industry-standard RS-232C serial interface. It can be used to attach the Portfolio to a wide variety of standard peripherals with serial interfaces such as modems, printers or bar code readers, that are available from a wide variety of manufacturers. With appropriate additional software (not included), It can be used to connect to the serial interface of another computer so as to use the Portfolio as a terminal, or to transfer data or programs. The internal application programs of the Portfolio contain several options that allow printing. Printed output can be directed by means of the built-in Setup program to a printer connected to the Serial Interface. The Setup program also allows you to set low level communications parameters to assure compatibility with the device it is connected to: baud rate, parity, number of data bits and number of stop bits. No file transfer or modem communications software is supplied with the product. The Serial Interface is a Bus Terminator Peripheral, with a Portfolio Bus Connector on the left and a nine-pin D-type connector on the right. It must be the last peripheral on the bus and cannot be used with another Bus Terminator Peripheral. You will also need a serial interface cable with a nine-pin D-type connector on one end and appropriate connector for the other device. Since the connector is a standard one used on IBM PC ATs and compatibles, appropriate cables for different applications are widely available. As with most RS-232C devices, it is often necessary to modify or build cables for particular applications. This peripheral takes its power from the batteries or A.C. Adaptor in the Main Unit and reduces battery life somewhat. MEMORY CARDS, Model HPC-201 (32K), HPC-202 (64k), HPC-203 (128K) Memory cards are small, credit card sized units that are not peripherals, strictly speaking, because they connect to a special card slot on left end of the Portfolio or to the Memory Expander Plus rather than to the Portfolio bus. Memory cards contain RAM memory whose contents is preserved continuously, even when removed from Portfolio, through the use of a small lithium battery. To the Portfolio software user, the Memory Card appears to be a disk drive, or "RAM disk," typically drive A: or B:, containing data files or programs. Memory Expanders, on the other hand, extend the main RAM memory that is used to load and run programs (although a portion of main memory is allocated to RAM disk C:) Through special adaptation of programs into a uniqe .RUN file type, programs may be run directly from a Memory Card, without being loaded into main memory as .EXE and .COM files are. Memory cards are available in three sizes: 32K bytes, 64K bytes and 128K bytes. Card slots also accept Program Cards, which contains ROM or PROM (OTP) rather than RAM, and are used primarily for the delivery of commerical software or custom programs. Like Memory Cards, Program Cards appear to the software user as "ROM disk" A: or B: and can contain .RUN programs. They come in sizes of 64K and128K. Larger versions that use bank-switching in banks of up to 128K bytes will be available in the future. PC MEMORY CARD DRIVE, Model HPC-301 This is a peripheral for a separate personal computer, not the Portfolio, that permits Portfolio Memory Cards of any capacity to be read and written from a personal computer using standard MSDOS commands such COPY, REN, TYPE, etc. It consists of a controller circuit board for the IBM PC bus and an external cabinet containing a slot for a single Memory Card, plus a software driver on diskette. It may be used with any IBM PC compatible computer supporting the AT bus. It is another faster means in addition to the Smart Parallel Interface to exchange files with a PC and can be used to exchange files when there is a considerable distance between the two machines. A.C. ADAPTOR, Models HPC-401 (117V) The A.C. Adaptor connects to the Portfolio by means of a special subminiature jack, and powers the Portfolio and all peripherals that are attached. When it is connected, battery power is saved, in fact it is not necessary to have batteries installed. The A.C. Adaptor does not act as a battery recharger. Only the Portfolio's A.C. Adaptor should be used and not a separately available universal type. The Portfolio Main Unit has a 60-pin bus connector on its right-hand side for the connection of peripheral devices.