Certainties For The New Electronic Market

Description

Communications Software for connections including dial-up lines

Main Article Text

The market for communications via telephone lines is expanding, and the technology must be refined in order to provide users an ever better performance, within a relatively constant operating environment which is that of the international and Italian telephone network. The cost of the modem is decreasing in a gradual and constant manner. It is enough to note that today a device capable of transmitting at 2400 bits per second costs about one and a half million lire that is roughly the price one would have had to pay five years ago for the purchase of a 300 bps modem. The insiders attention are then directed, not so much towards the optimization of production cost, but instead toward the search for methods that would maximize the power of today’s devices on lines that are notoriously noisy and unreliable. It is useless to have the output at 2400 bps when the useful speed is reduced to at least half, because of the signal’s distortion and the repetitive transmission of the same packets. The method of managing the transmission medium and packaging of the packages need to be modified in order to minimize this waste, so as to double the usable power without having to replace the modem. This is also true for leased lines where disturbances are limited, but the transmission speed is such (usually 9,200 bps) that even the slightest interference may cause the interruption of the flow reducing the efficiency of the modem that, in this case, is very expensive. Therefore, those who produce communication hardware or software have started working in the last few years on the development of techniques involving the compression of information and the suppression and correction of errors. There are two possible approaches to the problem: the first one consists of producing communication packages capable of being used on the common type of modem that are made of sophisticated protocols with error corrections and complex compression algorithms, the second one provides for the integration of these protocols and algorithms directly into the modem. Proponents of the software solution are of course the software houses who defend their thesis by arguing that an approach of this type is cheaper and does not force the user to be bound with a bond of fidelity (the need to use two identical modems on both sides of the line when using this type of integrated protocol built into the owners hardware) which is imposed by the manufacturers of modems.
The manufacturers replied saying that the only way to achieve adequate performance in error correction and compression is to let the internal microprocessor of the modem take charge of all the operations of coding and analysis, freeing the personal computer from often burdensome functions. Beyond these general considerations, there are of course many elements to be taken into consideration that may slant ones judgment in favor of one solution rather than another solution. Let’s start then, in this issue, by making an analysis of the software available on our market and in an upcoming issue we will address the subject of the intelligent modem.
All the protagonists of the error free software.
Among the software houses who are devoted to the problem of implementing protocols for error free transmissions, we find Crosstalk Communications, which is part of the Digital Communications Associates; Relay Communications; Hayes Microcomputer Products; Communications Research Group; Softronics Elmec Informatica, the only Italian representative in this arena. Crosstalk Communications Dca is specialized in the connection from micro to micro and is known for being among the founders and for having produced the communication packages for MS-DOS systems, Crosstalk XVI, which costs 540,000 lire. For several months now, Crosstalk Mk.4 is being sold that has a special protocol, which is able to manage multiple communications from a single workstation while simultaneously performing error checking stated X.PC. The Relay Communications group (formerly known as Vm Personal Computing) has instead built their fortune in the micro-mainframe communication market having established itself with the Relay Gold package. The program performs error control while it allows for emulation of the 3270 terminal and file transfer operations between micro and System 370. In version 3.0, (the most recent) Relay Gold can handle up to 16 simultaneous sessions for each workstation, with two-way transmission (full duplex) and error checking on each of the governed modems. The Communications Research Group proposes a particularly strong package with a type of disparate terminal emulation, but which is also suitable for the data transfer between personal computers. The program version that runs on MS-DOS systems is called PcBlast II and incorporates a special trial and error protocol and a function of data compression. Hayes Microcomputer Products is a leader in the manufacture of modems, however, for the last few years; Hayes has also been involved in the development of communication software. Its most recent creation in this field is Smartcom III, a powerful communication program with its own programming language, in addition to a trial and, error protocol, compression function and data encryption. Softronics, for its part, offers a solution very similar to Pc Blast, which is a package, called Softerm Pc, which has its strength in its emulation ability (45 types of terminals) and has a separate protocol, called Softrans, to transmit with the error control from micro to micro, or from micro to host. Pc Call of Elmec performs error correction with a model similar to that used for remote connections on the networks of IBM System Network Architecture. It also allows the management of up to four virtual channels of communication.
These six packages: Call Pc, Relay Gold, Softerm, Pc Blast II, Smartcom III and Crosstalk Mk.4 can work with any standard CCITT modem (International Telegraph and Telephone Consultative Committee) commercially available with the assumption that the investment will be small as compared to the level of overall performance once adapted to the needs of the average Italian user. On the other hand, none of the six packages provides a compression function on the data line which allows them to reach performances similar to those of a modem incorporating the Microcom networking Class 5 protocol. The modem absorbs the data of the serial line transparently with respect to the active program that is on the computer, and performs up to a 2:1 ratio compression. In every case, there is nothing prohibiting any error checking of the aforementioned software, in addition to the modem’s, compression ability, or even its ability to execute a double compression. It has been argued, in fact, that it is better analyzing the file to be transmitted before initiating the connection and decide, which system is the best for compression, rather than leave it to the modem to do all the work analyzing a bit at a time, as it is conveyed information along the serial line. There are those who are actually trying to find a perfect integration between hardware and software, integrating all of the insides of the communications package protocols identical to those existing in the equipment MNP. This is the case, for example, of Magicsoft and Walter Richie & Quinn (Quest last distributed by Com Tech of Rome). An approach of this kind, however, presents the drawback of increasing the size of the application package by at least 50 Kbytes, since it already serves program instructions for several software functions of the Microcom protocols.
SOFTWARE ERROR TEST
Crosstalk Mk.4 – Communication program distributed by Com Tech. – Via Peroglio 15, 00144 Rome, tel. 5984894 – selling at the price of 850,000 lire, but the price should decrease soon.
Pc Call – Data transfer software produced and marketed by Elmec Informatica – Valganna Avenue 34, 21100 Varese, tel. 0332 242175 – selling at the price of 500,000 lire.
Pc Blast II – Emulation and multiple communication software marketed by C.H. Ostfeld – via Lamarmora 6, 20122 Milan, tel. 02 5459682 – selling at a price of 630,000 lire.
Relay Gold – Emulation and communication packages sold and installed by Siosistemi – Via Cefalonia 24, 25124 Brescia, tel. 030 226361 –selling at the price of 500,000 lire.
Smartcom – Communication software distributed by PPE – Via Leonardo da Vinci 21 23-20090 Segrate – tel. 02 2137574 – selling at the price of 450,000 lire.
Softerm Pc – Multiple emulation and communication program distributed by. H. Ostfeld –selling at the price of 600,000 lire.

Roberto Mazzoni