(Models SC20:COAX and SF40: FIBER)
Now you can locate SCSI devices and computers where you want them. Paralan's Bus Extenders eliminate SCSI cable limitations by transmitting SCSI signals over coax or fiber optic cable with little or no throughput degradation.
Choose coax cable for economy and ease of installation, or fiber optic cable for longer distances, security and freedom from electromagnetic interference.
Cable length is the Small Computer Systems Interface (SCSI) standard's only defined major limitation. All devices connected to the SCSI single-ended parallel cabling must fit within a maximum of 6 meters (19.6 feet) total distance. Differential parallel cabling can extend this distance to 25 meters (82 feet), but at the cost of expensive cables, additional signal conversion hardware and high asynchronous throughput degradation over distance. Paralan SCSI Bus Extenders now drive SCSI communications beyond 300 meters (1000 feet).
The Paralan Model SC20 and SF40 Bus Extenders work with computers and devices that conform to the full SCSI ANSI X3T9.2 standard. This includes:
Paralan's proprietary transmission technique handles asynchronous SCSI data protocol with 1/128 the degradation throughput usually associated with REQ/ACK protocols, allowing high throughput over long distances. This technique also controls synchronous SCSI protocol transparently.
A Paralan Model SC20 SCSI to Coax Bus Extender converts SCSI parallel signals to serial information and transmits them through one of two RG62A coax cables (at a rate of over 100 Megabits per second) to another SC20 extender that converts the information back to SCSI signals. The two SC20 extenders communicate in full duplex mode and provide transparent communications for the SCSI bus. The distance between the SC20 extenders can be as long as 300 ft.
A Paralan Model SF40 operates in exactly the same manner as the coax version, except that the transmission medium is a fiber optic cable. The 62.5 micron graded index fiber optic cable between the SF40 extenders can be over 1000 ft long.
Paralan SC20 and SF40 extenders work within the full SCSI ANSI X3T9.2 standard. This includes managing the arbitration and disconnect/reconnect features of the latest systems, down to the SASI communications of earlier systems. Paralan extenders can control SCSI transmissions of up to 2.5 Mbytes/sec in asynchronous SCSI mode or 4 Mbytes/sec in synchronous SCSI mode. An extender can be connected anywhere on a SCSI cable, or directly to the SCSI interface.
Paralan SC20 and SF40 Bus Extenders are free standing units with separate dc power supplies.
For differential SCSI applications specify the differential versions of the SCSI Bus Extenders (Models SC20D or SF40D). Paralan also has Converters (Paralan SDxx series) for converting between differential and single-ended SCSI devices.
For further information, please contact Paralan at:
Paralan
7875 Convoy Court
San Diego, CA 92111
Tel: (619) 560-7266
Fax: (619) 560-8929
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