is done by keying in the codes of the events to be recorded; a chronometer (0.01 sec precision) permanently on makes it possible to record the instant each code is pressed. Thus, a data sequence is generated, describing the events recorded during the observational period by their codes and their respective occurrence times. This data set can then be transferred to a PC, through a RS 232 serial communications port. A data file containing the information generated by CompuLet 5 in ASCII can be obtained in the PC and can be handled by any standard data processing programme.
Wide range of application
The nature of the event associated to each code is defined by the researcher himself, which gives the device a great neutrality regarding its application areas. It can, in fact, be used either for event recording when frequency is the main concern (i. e., On/Off events) or for event recording when timing and/or latency is important. In the former, the number of times the event associated key was pressed is established, while in the latter, the event begins with pressing a key for the first time and ends with pressing it a second time. Nevertheless this kind of analysis should be carried out by the PC; Compulet 5 only provide the data acquisition tool. Programmable keyboard mode
The broad scope of this approach enables the range of events that can be recorded to widen considerably using the ten number keypad the device is provided with. According to the work mode selected by the researcher, it is possible to chose from as much as 10 (numeric keys only), 20 (numeric keys plus a function key), or 100 events (double-pressing a number key). User-selected acquisition mode
Data acquisition can be carried out continuously (just controlled by a START/ STOP key) or during a pre-programmed time-period. In this latter case, data-acquisition is automatically disabled once the observational period is over. Successive observation periods can be started either manually or automatically at pre-programmed intervals. It offers a four line digital display of 16 characters per line. CompuLet 5 provides information on the time elapsed from the beginning of the work session, as well as the last registered event, and the time it took place. This display provides also the messages necessary to handle communications with the PC and error messages (such as low battery load).
It is possible to get the accumulated total for each code through key commands, and examine each of the recorded observations. CompuLet 5 has more than enough capacity for data storing. It can record up to 6000 events without overloading the available memory (32 Kb). The data memory is battery fed, which allows the data to be safely kept even when the unit is off. On the other hand, it can operate for 24 hours (with batteries fully charged and depending on the work load). There are four rechargeable batteries (Ni Cd, AA) that provide the energy needed to operate the device. Each unit is supplied with a PC communications programme and a battery charger. Size: 211 x 100 x 26 (mm); approx. weight: 250 g. | 
