Texas Instruments BA-55

Datasheet legend
Ab/c: Fractions calculation
AC: Alternating current
BaseN: Number base calculations
Card: Magnetic card storage
Cmem: Continuous memory
Cond: Conditional execution
Const: Scientific constants
Cplx: Complex number arithmetic
DC: Direct current
Eqlib: Equation library
Exp: Exponential/logarithmic functions
Fin: Financial functions
Grph: Graphing capability
Hyp: Hyperbolic functions
Ind: Indirect addressing
Intg: Numerical integration
Jump: Unconditional jump (GOTO)
Lbl: Program labels
LCD: Liquid Crystal Display
LED: Light-Emitting Diode
Li-ion: Lithium-ion rechargeable battery
Lreg: Linear regression (2-variable statistics)
mA: Milliamperes of current
Mtrx: Matrix support
NiCd: Nickel-Cadmium rechargeable battery
NiMH: Nickel-metal-hydrite rechargeable battery
Prnt: Printer
RTC: Real-time clock
Sdev: Standard deviation (1-variable statistics)
Solv: Equation solver
Subr: Subroutine call capability
Symb: Symbolic computing
Tape: Magnetic tape storage
Trig: Trigonometric functions
Units: Unit conversions
VAC: Volts AC
VDC: Volts DC
Years of production:   Display type: Numeric display  
New price:   Display color: Black  
    Display technology: Liquid crystal display 
Size: 6"×3"×1" Display size: 8(5+2) digits
Weight: 4 oz    
    Entry method: Algebraic 
Batteries: 2×"LR44" button cell Advanced functions: Exp Fin Cmem 
External power:   Memory functions:
I/O: Printer port     
    Programming model: Keystroke entry 
Precision: 11 digits Program functions:  
Memories: 5(0) numbers Program display: Keycode display  
Program memory: 40 program steps Program editing: Overwrite capability  
Chipset:   Forensic result:  

ba55.jpg (25980 bytes)Yet another "almost programmable", the BA-55 is a business oriented calculator from Texas Instruments. Although obviously, business functions replaced common scientific functions such as trigonometric commands on this machine, it still unmistakably belongs to the same family as the TI-55-II or TI-55-III.

A remarkable oddity on this calculator is the presence of a printer port; this port connects to the same PC-200 printer as the high-end TI-66 programmable. (It'd be interesting to know if there were any other TI calculators with this proprietary serial port.) The calculator is even capable of listing programs, complete with alphabetic mnemonics! This is probably the lowest-end programmable calculator with such a program listing capability.

The programming model is very similar to that of the TI-55-II. No branches, loops, or conditionals, just sequential execution of a memorized series of keystrokes. The program area is too small for a Gamma function example, so here is Stirling's formula instead:

00 61    STO
01 01    1
02 85    +
03 01    1
04 02    2
05 54    1/x
06 55    ÷
07 71    RCL
08 01    1
09 50    ex
10 55    ÷
11 71    RCL
12 01    1
13 53    √
14 65    ×
15 02    2
16 93    .
17 05    5
18 00    0
19 06    6
20 06    6
21 95    =
22 91    EXC
23 01    1
24 60    yx
25 51    x-y
26 65    ×
27 71    RCL
28 01    1
29 95    =
30 13    R/S
31 37    RST