Tascam MMR-8 - Manual (Page 33)

MMR-8 TASCAM MMR-8 Owner’s Manual • Chapter 2 • Installation 33
Connecting External SCSI Media
The MMR-8 SCSI interface card is pre-set to SCSI ID 7. The internal Kingston drive receiver in the
MMR-8 is set to SCSI ID 0. Each device added in the SCSI chain must have a unique SCSI ID number or
else the MMR-8 will not boot properly.
External SCSI connections should be made using the shortest possible length of double-shielded SCSI-2
cables with 110 ohms impedance. Only the last drive in the chain is terminated. All other drives must
have their terminating resistors removed or have termination jumpers set to off (including those drives
placed in the MMR-8 internal drive slot). SCSI cables are readily available from most computer stores.
For the most reliable operation, the total length of SCSI cabling must not exceed 15 to 20 feet.
Drives with capacities of up to 9 GB have been tested and found suitable for use with the MMR-8. The
MMR-8 system records all audio in separate uncompressed 16-bit or 24-bit linear files. Approximately 5
MB (Megabytes) of disk space is required for each minute of audio recorded per track. Thus a 4 GB drive
can hold about 12 track hours of 16-bit audio, while a 2 GB drive will hold about 6 track hours. See the
disk time chart in Appendix F for more information on disk recording time at different sample rates, bit
depths, and track counts.
SCSI Cables
There is a considerable difference in quality and performance of cables used to connect SCSI devices. It is
imperative that users pay close attention to this issue.
Cable Quality
High quality SCSI cables are essential for proper MMR/MMP system performance. Low quality cables,
which are often thin, may cause data transmission errors, file corruption, and system malfunctions. This is
often due to improper and insufficient grounding, incorrect pin wiring, and unwired pins. The following
SCSI cable manufacturers are highly recommended as a source for MMR/MMP SCSI cables:
Cable Length and Device Support
The MMR/MMP SCSI host card supports from one to eight SCSI devices. However when one to four
SCSI devices are connected, total cable length should not exceed three meters. When five to eight SCSI
devices are connected, total cable length should not exceed 1.5 meters. Note that total cable length
includes the internal cabling in carriers or drive bays. Thus if a 4-bay drive enclosure contains ribbon
cable internally that measures one meter in length, the external cable must not exceed 2 meters. Improper
cable length often causes an MMR system to freeze while mounting volumes. (Note: Paralan can provide
custom-length SCSI cables).
Black Box Corporation -
www.blackbox.com
1000 Park Drive Lawrence, PA 15055-1018
Tel: 724-746-5500 || Fax: 724-746-0746
email [email protected] Paralan Corporation -
www.paralan.com
4655 Ruffner St., San Diego, CA 92111
Tel. (619) 560-7266 || Fax 619-560-8929
email: [email protected]