The PAR96 modem is the first high-speed modem for packet radio that does not require a TNC or a slotcard. It is simply connected to the LPT interface of the IBM PC. The modem is 100% compatible to the widespread G3RUH FSK standard.
The modem is based on the DF9IC/DK7WJ design of the G3RUH modem. Data scrambling and digital carrier detection (DCD) are performed by the terminal software. Data is transmitted from and to the modem in serial bursts via the LPT interface. This leads to a very low interrupt rate in the PC. A bidirectional interface is not required.
The modem is connected to the LPT interface via a standard printer cable. It requires an external power supply (8-13V, 160mA). Like any other 9600Bd FSK modem, the PAR96 requires a transceiver capable of passing a wide-band FSK signal, usually either a purpose-built rig such as the TEKK KS-900, KS-960 or KS-1000, or a modified crystal-controlled radio. Alternatively it is possible to modify a some synthesized transceivers or buy a "9600Bd-ready" rig, but in either of those cases the performance is most likely not going to be optimal. To enable a wide range of transceivers to be used, eight different transmitter FIR filter characteristics can be set by DIP switches.
Currently, the modem is supported by BayCom terminal program 1.60. G8BPQ, TFPCX, and FlexNet. The BayCom terminal software allows simultaneous operation of the PAR96 on the LPT interface and a 1200Bd serial modem on the COM interface.
The modem is assembled on a double-sided PCB, size 100 * 100mm. The main logic was implemented in three GALs (20V8). Kit and assembled unit come with an HF-proof aluminium case. All connectors are on the rear side of the modem, and all switches and trimmers are accessible from the front panel.
Technical specifications:
Size: 100mm*100mm*30mm
100% G3RUH-compatible FSK-signal
Power supply: 8-13V AC or DC, 160mA, alternatively 5V, 160mA
Centronics connector: 25p. Sub-D connector, male
Radio connector: 9p. Sub-D connector, male
Deviation adjustment with trimmer, accessible from front panel
LEDs for power supply and PTT
8 different filter characteristics
System requirements: 10 MHz PC, IBM AT compatible
Comprehensive hard and software documentation, incl. circuit diagram.
Now available
The PAR96 now has "little brothers" in the PICPAR and SMD-PICPAR modems. They have all the features of their big brother, except for the audio filter DIP switches, but don't need a cable to connect to the parallel port. In most cases, they can also be powered from the LPT port and do not need an external power supply.
