TM
11-5835-243-34/EE641-AA-MMI-010/E154
MTT/TO
31S3-4-110-1
b. Enclosure. The enclosure is of rylon resin
Power Consumption. . . . . . . . .10 W max. standby
40 W max. operating
construction. Its rigidity assures accurate tape
100 W max. starting
guidance and minimum dynamic skew under
Capstan Drive . . . . . . . . . . . . . . Direct drive, servo-controll-
vibration and shock environment. The access door
ed, bidirectional dc motor.
and cover are made of translucent plastic. The
(3) Signal Characteristics.
access door is spring-loaded and closes
Line Receiver Requirements:
automatically when the magnetic tape cartridge is
Voltage Levels:
removed from the tape transport. This retractable
LOW (logic l) . . . . . . . . . . . . . . . 0.0 to +l.2volts
HIGH (logic 0) . . . . . . . . . . . . . .+2.5 to +4.5volts
cover protects the tape from physical damage and
Current Levels:
contamination until the tape cartridge is in position
LOW (logic l) . . . . . . . . . . . . . . .+0.l ma max.
within the tape transport. A rotary detent on the
HIGH (logic 0) . . . . . . . . . . . . . .- 0.l ma max.
cartridge enclosure mechanical prevents accidental
Input Transitions. . . . . . . . . . . . Compatible with all standard
integrated circuit transition
erasure or overwriting of data on the tape. When the
configurations. Rise and fall
detent is in the PROT (protected) position, write
times limited to 1 micro-
permit switch S2 on the tape deck is not actuated,
second max.
and write current is inhibited.
Output Driver Capabilities:
The tape tensioning
C. Tape Tensioning.
Voltage Levels:
mechanism consists of two freed position belt idlers,
Low (logic 1) . . . . . . . . . . . . . . . .0.0 to +0.5 volt
HIGH (logic 0) . . . . . . . . . . . . . .+2.5 to +4.5 volts
one mobile or floating pressure roller and an endless
(5.5 volts max.)
elastic belt (fig. 1-4). All idlers are made of non-
Current Levels:
magnetic stainless steel and mounted on precision,
LOW (logic l), . . . . . . . . . . . . . .100 ma max.
permanently lubricated ball bearings to assure fast
HIGH (logic 0) . . . . . . . . . . . . . . Outputs are open collector
start/stop accelerations. The elastric belt is made of
and require an external pull-
up resistor (220 to 330 ohms
special composition silicone which ensures
nominal)
negligible variation in the elasticity over the
(for
Transitions
Output
operating temperature range and prevents per-
combined cable and load
manent damage during low temperature storage.
capacitance of 500 pf and
line logic level):
The supply and take-up reels and the pressure roller
RISE time . . . . . . . . . . . . . . . . . 0.200 microsecond max. with a
are in nonslipping contact with the elastic belt so
1000 ohm pull-up
that tape tension is maintained while the cartridge
FALL time . . . . . . . . . . . . . . . . . 0.300 microsecond max.
is removed from the tape transport. The nonslipping
(4) Performance Characteristics.
contact is ensured by a predetermined amount of
Data Capacity:
elongation of the belt at the time of installation,
3M Company type 890 . . . . . . . .46.5 megabits
Recording format. . . . . . . . . . . . 9-track 8 8 8 b p i NRZ1
giving it a fixed initial tension.
ANSI/IBM compatible
d. Drive Mechanism. The magnetic tape is wound
Data Transfer Rate . . . . . . . . . . 12k bytes per second at 22.5
onto two flangeless aluminum alloy reel hubs and is
ips
guided between two reels by two rotating tape
Magnetic Head Assembly. . . . . 9-track read-after-write,
guides made of nonmagnetic stainless steel and the
0.150 inch gap-to-gap, and full
width erase before write in the
spring-loaded, polyurethane-coated pinch roller (fig.
forward direction
Tape Speed . . . . . . . . . . . . . . .22.5 ips read/write; 45 ips
mounted on precision, permanently lubricated ball
search
bearings. The magnetic tape has reflective markers
Start/Stop Time . . . . . . . . . . . . . 33 milliseconds at 22.5 ips;
on the back side of the tape for beginning-of-tape
66 milliseconds at 45 ips
Search Speed . . . . . . . . . . . . . . .45ips
(BOT) and end-of-tape (EOT) sensing, and includes
Instantaneous Speed
three punched holes for physical end-of-tape sensing
Variations . . . . . . . . . . . . . . . . 3 percent max.
at each end of the tape.
Long-Term Speed Variations . .3 percent max.
Peak-to-Peak Jitter . . . . . . . . . .5 percent max.
1-9. Tabulated Data
Skew . . . . . . . . . . . . . . . . . . . . . . ANSI compatible
Data Reliability . . . . . . . . . . . . . 1 unrecoverable error in 108
a. Tape Transport.
bits; 1 unrecoverable error in
(1) Physical Characteristics.
1 07 bits
Height . . . . . . . . . . . . . . . . . . . .7.60 in.
Status Lines
Width . . . . . . . . . . . . . . . . . . . .4.04 in.
(TTL Compatible). . . . . . . . . . Ready (magnetic tape cartridge
Depth . . . . . . . . . . . . . . . . . . . . .15.81 in. (handle extended)
installed correctly and door
Weight . . . . . . . . . . . . . . . . . . . .13.51b.
closed), EOT marker, BOT
(2) Electrical Characteristics.
marker, rewinding,
and
Input Voltage . . . . . . . . . . . . . . .28 4 vdc
selected
1-7
