PC104-DIO48
User’s Manual

Revision 4A
April, 2001

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HM PC104-DIO48.lwp

Table of Contents
1 SOFTWARE INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 HARDWARE INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.1 BASE ADDRESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.2 INSTALLING THE BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.3 CABLING TO THE DIO48 CONNECTOR . . . . . . . . . . . . . . . . . . . . 3
2.4 SIGNAL CONNECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.5 UNCONNECTED INPUTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.6 CONNECTOR DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3 CONTROL & DATA REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1 DIGITAL I/O REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5 ELECTRONICS AND INTERFACING . . . . . . . . . . . . . . . . . . . . . . . . 12
5.1 PULL UP & PULL DOWN RESISTORS . . . . . . . . . . . . . . . . . . . . . 12
5.2 TTL TO SOLID STATE RELAYS . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.3 VOLTAGE DIVIDERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.4 LOW PASS FILTERS DE-BOUNCE INPUTS . . . . . . . . . . . . . . . . . 17

This page is blank.

1 SOFTWARE INSTALLATIONThe board has switches and jumpers to set before installing the board inyour computer. By far the simplest way to configure your board is to use
the InstaCalTM program provided as part of your software package.
InstaCalTM will show you all available options, how to configure thevarious switches and jumpers (as applicable) to match your application
requirements, and will create a configuration file that your application
software (and the Universal Library) will refer to so the software you use
will automatically know the exact configuration of the board.
Please refer to the Extended Software Installation Manual regarding the
installation and operation of InstaCalTM. The following hard copy
information is provided as a matter of completeness, and will allow you
to set the hardware configuration of the board if you do not have
immediate access to InstaCalTM and/or your computer.

2 HARDWARE INSTALLATION
2.1 BASE ADDRESSThe PC104-DIO48 employs the PC bus for power, communications anddata transfer. As such it draws power from the PC, monitors the addresslines and control signals and responds to it's I/O address, and it receives
and places data on the eight data lines.
The base address is the starting location that software writes to and reads
from.
The
base
address
switch is the means forsettingthebase
address. Each switch
position corresponds toone of the PC bus
address lines.
The
down position activatesthat address bit.

1

2 3 4

5

6 7

SWITCH
1
2
3
4
5
6
7

HEX
200
100
80
40
20
10
08

BASE ADDRESS SWITCHES – 300h Shown.

Figure 2-1. Base Address Switches
1

The actual address is constructed by calculating the HEX or decimal
number Base Address Select Switches which corresponds to the baseaddress bits the PC104-DIO48 will respond to. For example, in Figure
2-1, switches 1 and 2 down, all others are up. Switch 1 = 200 hex (512decimal) and switch 2 = 100 hex (256 decimal). When added together
they equal 300 hex (768 decimal).
Certain address are reserved for use by the PC (Table 2-1). Others arefree and can be used by the PC104-DIO48 and other expansion boards.
We recommend that BASE = 300 hex (768 decimal) be tried first. See
Figure 2-2 for the orientation of the switch block.
Table 2-1. PC I/O Addresses
HEX
RANGE
000-00F
020-021040-043060-063060-064070-071080-08F
0A0-0A1
0A0-0AF
0C0-0DF
0F0-0FF
1F0-1FF
200-20F
210-21F
238-23B
23C-23F
270-27F
2B0-2BF

FUNCTION
8237 DMA #1
8259 PIC #1
8253 TIMER
8255 PPI (XT)8742 CONTROLLER (AT)
CMOS RAM & NMI MASK (AT)DMA PAGE REGISTERS
8259 PIC #2 (AT)NMI MASK (XT)8237 #2 (AT)80287 NUMERIC CO-P (AT)HARD DISK (AT)GAME CONTROLEXPANSION UNIT (XT)BUS MOUSEALT BUS MOUSEPARALLEL PRINTER
EGA

HEX
RANGE
2C0-2CF
2D0-2DF
2E0-2E7
2E8-2EF
2F8-2FF
300-30F
310-31F
320-32F
378-37F
380-38F
3A0-3AF
3B0-3BB
3BC-3BF
3C0-3CF
3D0-3DF
3E8-3EF
3F0-3F7
3F8-3FFFUNCTION
EGA
EGA
GPIB (AT)SERIAL PORTSERIAL PORTPROTOTYPE CARD
PROTOTYPE CARD
HARD DISK (XT)
PARALLEL PRINTER
SDLC
SDLC
MDA
PARALLEL PRINTEREGACGASERIAL PORTFLOPPY DISKSERIAL PORTThe PC104-DIO48 BASE switch may be set for address in the range of000 to 3F8 so it should not be hard to find a free address area for your
PC104-DIO48. Once again, if you are not using IBM prototyping cards
or some other board which occupies these addresses, then 300-31Fh arefree to use. Addresses not specifically listed, such as 390-39Fh, are free.

22.2 INSTALLING THE BOARD
1. Turn the power off.
2. Push the board firmly down into the expansion bus connector. If it is
not seated fully it may fail to work and could short circuit the PC bus
power onto a PC bus signal. This could damage the motherboard in yourPC as well as the PC104-DIO48.

2.3 CABLING TO THE DIO48 CONNECTOR
The connector is a standard 50-pin, male, header connector. A mating
female connector (C50FF-##) may be purchased from Measurement
Computing.

2.4 SIGNAL CONNECTION
All the digital outputs/inputs on the connector are CMOS TTL. TTL is
an electronics industry term, short for Transistor Transistor Logic, which
describes a standard for digital signals which are either 0V or 5V(nominal).
Under normal operating conditions, the voltages on the 82C55 pins
range from near 0 volts for the low state to near 5.0 volts for the highstate. Before connecting the PC104-DIO48 to external devices, review
the electrical specification in this manual to ensure that the boards input
voltage specifications are not exceeded. In addition to voltage and load
matching, digital signal sources often need to be de-bounced. Moredetails on digital interfacing are in the section on Interface Electronics inthis manual.

3

Figure 2-2. PC104-DIO48 Board Layout and Pin 1 Location
IMPORTANT NOTE: The PC104-DIO48 uses two 82C55 digitalchips for digital I/O. The 82C55 digital I/O chip initializes all ports as
inputs on power up and reset. A TTL input is a high impedance input.
If you connect another TTL input device to the 82C55 it will probably beturned ON every time the 82C55 is reset, or, it might be turned OFF
instead. Remember, an 82C55 which is reset is in INPUT mode.
To safeguard against unwanted signal levels, all devices being controlled
by an 82C55 should be tied low (or high, as required) by a 2.2K ohm
resistor.
You will find positions for pull up and pull down resistor packs on your
PC104-DIO48 board. To implement these, please turn to the applicationnote on pull up/down resistors.

2.5 UNCONNECTED INPUTS
Keep in mind that unconnected inputs float. If you are using a
PC104-DIO48 board for input, and have unconnected inputs, ignore thedata from those lines.
4In other words, if you connect bit A0 and not bit A1, do not be surprised
if A1 stays low, stays high or tracks A0. It is unconnected and so, is not
specified. The 82C55 is not malfunctioning. In the absence of apull-up/down resistor, any input which is unconnected is unspecified.
You do not have to tie input lines, and unconnected lines will not affectthe performance of connected lines. Just make sure that you mask out
any unconnected bits in software.

2.6 CONNECTOR DIAGRAM
The connector accepts female 50-pin header connectors, such as thoseon the C50FF-2, a 2-foot cable with connectors.

BASE + 4, 5, 6

BASE + 0, 1, 2

If frequent changes to signal connections or signal conditioning isrequired, please refer to the information on the CIO-TERM100,
CIO-SPADE50 and CIO-MINI50 screw terminal boards.

Figure 2-2 I/O Connector
53 CONTROL & DATA REGISTERS
We recommend that you use the Universal Library for all high level
programming. The following is basic information on the 82C55 control
and data registers and a table of control bytes for MODE 0 only. To
learn more about the other 82C55 modes, you will need the component
data book available from the component manufacturer.
Each PC104-DIO48 has two 82C55 parallel I/O chips. Each chip
contains three data and one control register occupying four consecutive
I/O address locations. The number of I/O locations occupied by aPC104-DIO48 board is equal to 4 times the number of 82C55 chips on
the board or eight total.
The first address, or BASE ADDRESS, is determined by setting a bankof switches on the board.
The register descriptions follow all follow the format:
7
A7

6
A6

5
A5

4
A4

3
A3

2
A2

1
A1

0
A0

The numbers along the top row are the bit positions within the 8-bit byte
and the numbers and symbols in the bottom row are the functions
associated with each bit.
To write to or read from a register in decimal or HEX, the bit weights inTable 2-1 apply:
Table 3-1. Bit Weights
BIT POSITION
0
1
2
3
4
5
6
7

DECIMAL VALUE
1
2
4
8
16
32
64
128

HEX VALUE
1
2
4
8
10
20
40
80

To write a control word or data to a register, the individual bits must be
set to 0 or 1 then combined to form a byte. Data read from registers
must be analyzed to determine which bits are on or off.
6

The method of programming required to set/read bits from bytes isbeyond the scope of this manual. It is covered in most Introduction To
Programming books.
Board registers and their function are listed on the following table. Eachregister has eight bits which may be one byte of data or they may beeight individual read/write functions.
Table 3-2. Board I/O Addresses
ADDRESS
BASE + 0
BASE + 1
BASE + 2
BASE + 3
BASE + 4
BASE + 5
BASE + 6
BASE + 7

READ FUNCTIONPort A Input of 1st 82C55
Port B Input
Port C Input
None. No read back on
82C55
Port A Input of 2nd 82C55
Port B Input
Port C Input
None. No read back on
82C55

WRITE FUNCTIONPort A Output (1st 8255)
Port B Output
Port C Output
Configure 1st 82C55
Port A Output (2nd 8255)
Port B Output
Port C Output
Configure 2nd 82C55

3.1 DIGITAL I/O REGISTERS
PORT A DATABASE ADDRESS + 0 (1st 82C55)
BASE ADDRESS + 4 (2nd 82C55)
7
A7

6
A6

5
A5

4
A4

3
A3

2
A2

1
A1

0
A0

3
B3

2
B2

1
B1

0
B0

PORT B DATABASE ADDRESS + 1 (1st 82C55)
BASE ADDRESS + 5 (2nd 82C55)
7
B7

6
B6

5
B5

4
B4

Ports A & B may be programmed as input or output. Each is written to
and read from in bytes, although for control and monitoring purposes,
individual bits are typically used.
7

Bit set/reset and bit read functions require that unwanted bits be masked
out of reads and ORed into writes.
PORT C DATABASE ADDRESS + 2 (1st 82C55)
BASE ADDRESS + 6 (2nd 82C55)
7
C8
PCH3

6
C7
PCH2

5
C6
PCH1

4
C5
PCH0

3
C4
PCL3

2
C3
PCL2

1
C2
PCL1

0
C1
PCL0

Port C can be used as one 8-bit port of either input or output, or it can be
split into two 4-bit ports which can be independently input or output.
The notation for the upper 4-bit port is PCH3 - PCH0, and for the lower,
PCL3 - PCL0.
Although it can be split, every read and write to port C carries eight bitsof data so unwanted information must be ANDed out of reads, andwrites must be ORed with the current status of the other port.
OUTPUT PORTS
In 82C55 mode 0 configuration, ports configured for output hold theoutput data written to them. This output byte may be read back byreading a port configured for output.
INPUT PORTS
In 82C55 mode 0 configuration, ports configured for input read the stateof the input lines at the moment the read is executed, transitions are notlatched.
For information on modes 1 (strobed I/O) and 2 (bi-directional strobed
I/O), refer to an Intel or AMD data book, 82C55 data sheet.
82C55 CONTROL REGISTERS
BASE ADDRESS + 3 (1st 82C55)
BASE ADDRESS + 7 (2nd 82C55)
7
MS

6
M3

5
4
M2
A
Group A

3
CU

8

2
M1

1
B
Group B

0
CLThe 82C55 can be programmed to operate in Input/ Output (mode 0),
Strobed Input/ Output (mode 1) or Bi-Directional Bus (mode 2).
Information on programming the 82C55 in mode 0 is included here.
Those wishing to use the 82C55 in modes 1 or 2, must procure a data
sheet from Intel Corporation Literature Department. Visit their web site
to obtain this data sheet.
When the PC is powered up or RESET, the 82C55 is reset. This places
all 24 lines in Input mode and no further programming is needed to use
the 24 lines as TTL inputs.
To program the 82C55 for other modes, the following control code byte
must be assembled into an 8-bit byte.
MS = Mode Set. 1 = mode set active
M3

M2

Group A Function00Mode 0 Input / Output

01Mode 1 Strobed Input / Output

1

X

Mode 2 Bi-Directional Bus

A

B

CL

CH

Independent Function

1

1

1

1

Input

0

0

0

0

OutputM1 = 0 is mode 0 for group B. Input / Output
M1 = 1 is mode 1 for group B. Strobed Input / Output
The Ports A, B, C-High, and C-Low, can be independently programmed
for input or output.
The two groups of ports, group A and group B, may be independently
programmed in one of several modes. The most commonly used mode ismode 0, input/output mode. The codes for programming the 82C55 inmode 0 are listed in Table 2-3.

9

Table 2-3. Mode 0 - Port I/O Select Codes
D4
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1

D3
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1

D1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1

D0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1

HEX
80
81
82
83
88
89
8A
8B
90
91
92
93
98
99
9A
9B

DEC
128
129
130
131
136
137
138
139
144
145
146
147
152
153
154
155

A
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
IN
IN
IN
IN
IN
IN
IN
IN

CU
OUT
OUT
OUT
OUT
IN
IN
IN
IN
OUT
OUT
OUT
OUT
IN
IN
IN
IN

NOTE: D7 is always 1; D6, D5, and D2 are always 0.

10

B
OUT
OUT
IN
IN
OUT
OUT
IN
IN
OUT
OUT
IN
IN
OUT
OUT
IN
IN

CL
OUT
IN
OUT
IN
OUT
IN
OUT
IN
OUT
IN
OUT
IN
OUT
IN
OUT
IN

4 SPECIFICATIONSPower consumption+5V Operating

130 mA typical, 200 mA max

Digital Input / Output
Digital Type
Configuration

Number of channels
Output High
Output Low
Input High
Input Low
Power-up / reset state
Miscellaneous

82C55
4 ports of 8, 4 ports of 4,
programmable by port as input or
output48 I/O
3.0 volts min @ −2.5 mA
0.4 volts max @ 2.5 mA
2.0 volts min, +5.5 volts absolute max
0.8 volts max, −0.5 volts absolute min
Input mode (high impedance)
Locations provided for installation ofpull-up or pull-down resistors.

Environmental
Operating temperature range 0 to 50°C
Storage temperature range−20 to 70°C
Humidity
0 to 90% non-condensing

115 ELECTRONICS AND INTERFACING

This brief introduction to the electronics most often needed by digital
I/O board users covers the following subjects:yPull-up/pull-down resistorsyTransistorsyPower MOSFETsy

Solid State RelaysyVoltage dividersy

Low pass filters for digital inputsyNoise; sources and solutions
IMPORTANT NOTE:
WHEN AN 82C55 IS POWERED ON OR ISRESET, ALL PINS ARE SET TO HIGHIMPEDANCE INPUT.

The implication of this is that if you have output devices such as solidstate relays, they may be switched on whenever the computer is poweredon or reset. To prevent unwanted switching and to drive all outputs to a
known safe state after power-on or reset, pull all pins either high (to+5VDC ) or low (to GND) through a 2.2K ohm resistor.
To install pull up/down resistor packs, refer to the following applicationnote.

5.1 PULL UP & PULL DOWN RESISTORSThis section deals with pull up/pull down resistors and 82C55 digital I/O
chips.
Whenever the 82C55 is powered-on or reset, the control register is set toa known state; that state is mode 0, all ports set to inputs.
When used as an output device to control other TTL input devices, the82C55 applies a voltage level of near 0V for low and near 5V for high.
12The concept of voltage level of an 82C55 in input mode is meaningless.
Do not connect a volt meter to the floating input of an 82C55. It willshow you nothing of meaning. In input mode the 82C55 is in 'high Z' orhigh impedance. If your 82C55 were connected to another input chip(the device you were controlling), the inputs of that chip are left floating
whenever the 82C55 is in input mode.
If the inputs of the device you are controlling are left to float, they may
float up or down. The direction they float depends on the characteristicsof the circuit and is unpredictable! This is why it often appears that the
82C55 has gone high after power-up. The result can be that yourcontrolled device gets turned on! This is why you need pull up/pull
down resistors.
Figure 4-1 shows an 82C55 digital output with a pull-up resistor
attached.

The
pull-upresistor
provides a reference to+5V while its value of
2,200 ohms allows about
2.3 mA to flow throughthe circuit.

If the 82C55 is reset andenters high impedance
input mode, the line ispulled high. At that point,
both the 82C55 AND thedevice being controlled
will “see” a high signal.

Figure 5-1. Output Being Pulled Up

If the 82C55 is in output mode, the 82C55 has enough power to override
the pull-up resistor's high signal and drive the line low. If the 82C55
asserts a high signal, the pull-up resistor guarantees that the line goes tohigh (about +5V).
Of course, a pull-down resistor accomplishes the same task except thatthe line is pulled low when the 82C55 is reset. The 82C55 has morethan enough power to drive the line high.
13

The board is equipped with positions for pull-up/down resistors Single
Inline Packages (SIPs). The positions are marked RN1 through RN6 andare located beside the 82C55s.
A 2.2K ohm, 8-resistor SIP is made of eight, 2.2K resistors. One side ofeach resistor are all connected to a common point. The other ends go toeight SIP pins. The common line, at one end of the SIP, is marked with adot or a line.
The SIP may be installed as pull-up or pull-down. At each location,
RN1 - RN6, there are 10 holes in a line. One end of the line is marked“HI”, the other end is marked “LO”. The eight holes in the middle areconnected to the eight lines of a port, A, B, or C. To ‘pull up’ the digital
lines for a particular port, install the SIP resistor with the marked end
toward the ‘HI’ label. To pull down the digital lines for a particular
port, install the SIP resistor with the marked end toward the ‘LO’ label.
Install and solder the SIP in place.
A resistor value of 2.2K is recommended. Use other values only if you
have calculated the necessity of doing so.

5.2 TTL TO SOLID STATE RELAYS
Many applications require digital outputs to switch AC and DC voltage
motors on and off and to monitor AC and DC voltages. These AC andhigh DC voltages cannot be controlled or read directly by the TTL
digital lines of a PC104-DIO48.
Solid State Relays, such as those available from Measurement
Computing Corp. allow control and monitoring of AC and high DC
voltages and can provide 750V isolation. Solid State Relays (SSRs) are
the recommended devices for interfacing to AC and high DC signals.
The most convenient way to use solid state relays with a PC104-DIO48
board is to purchase a Solid State Relay Rack. A SSR Rack is a circuitboard with output buffer chips which are powerful enough to switch the
SSR. It provides sockets for SSRs.
SSR Racks are available from the Measurement Computing Corporation.
If you only want to drive one or two SSRs, all you need is a 74LS244
output buffer chip between the 82C55 output and the SSR. Of course
the SSR will need a 5 volt power source as well.
14

5.3 VOLTAGE DIVIDERS
If you wish to measure a signal which varies over a range greater than
the input range of a digital input, a proper voltage divider will drop thevoltage of the input signal to a safe level.
A voltage divider takes advantage of Ohm's law, which states,
Voltage = Current * Resistanceand Kirkoff's voltage law which states,
The sum of the voltage drops around a circuit will be equal tothe voltage drop for the entire circuit.
Implied in the above is that any variation in the voltage drop for thecircuit as a whole will have a proportional variation in all the voltage
drops in the circuit.
In a voltage divider, the voltage across one of the resistors in a circuit is
proportional to the ratio of that resistor to the total resistance in thecircuit.
Therefore, you setup a voltage divider choosing two resistors with theproper proportions relative to the full scale of the voltage input and the
maximum signal voltage to the board.

Figure 5-2. Voltage Divider

15

Dropping the voltage proportionally is called attenuation. The formulafor attenuation is:

Attenuation = R1 + R2

The variable Attenuation is the proportional
difference between the signal voltage max andthe full scale of the analog input.

R2

2 = 10K + 10K
10K

R1 = (A-1) * R2

For example, if the signal varies between 0 and
20 volts and you wish to measure that with ananalog input with a full scale range of 0 to 10
volts, the Attenuation is 2:1 or just 2.

For a given attenuation, pick a handy resisitor
and call it R2, the use this formula to calculate
R1.

Digital inputs may also require the use of voltage dividers. For example,
if you wish to measure a digital signal that is at 0 volts when off and 24
volts when on, you cannot connect that directly to the digital inputs. The
voltage must be dropped to 5 volts max when on. The attenuation is24:5 or 4.8. Use the equation above to find an appropriate R1 if R2 is
1K. Remember that a TTL input is 'on' when the input voltage is greaterthan 2.5V but less than 5.0V.

IMPORTANT NOTE: The resistors, R1 and R2, aregoing to dissipate power in the divider circuit according
to the equation, Current = Voltage / Resistance And
power (watts) is current-squared times resistance(W=I2*R). The higher the value of the resistance (R1 +R2) the less power dissipated by the divider circuit.
Here is a simple rule:
For Attenuation of 5:1 or less, no resistor should be lessthan 10K.
For Attenuation of greater than 5:1, no resistor shouldbe less than 1K.
16

5.4 LOW PASS FILTERS DE-BOUNCE INPUTS
A low pass filter is placed on the signal wires between a signal and an
DIO board. It attenuates frequencies greater than the cut-off frequency
preventing them from entering the digital inputs.
The key term in a low pass filter circuit is cut-off frequency. The cut-off
frequency is that frequency above which no variation of voltage withrespect to time may enter the circuit. For example, if a low pass filter
had a cut-off frequency of 30 Hz, interference associated with line
voltage (60 Hz) would be filtered out but a signal of 25 Hz would beallowed to pass.
Also, in a digital circuit, a low pass filter might be used to “de-bounce”(filter) an input from a switch or external relay. (Unless switch/relay
contacts are mercury-whetted, they tend to bounce briefly on closure,generating a pulsating noise signal. This can easily lead to erroneous
counts unless filtered out.)

Figure 5-3. Low-Pass Filter

17

A simple low-pass filter may be constructed from one resistor (R) and
one capacitor (C) (Figure 5-3). The cut-off frequency is determinedaccording to the formula:
Fc =

and
R=

1
2πRC

Where π= 3.14...
R = ohms
C = farads

1
2π C Fc

Fc = cut-off frequency in cycles/second.

18

EC Declaration of Conformity
We, Measurement Computing Corporation, declare under sole responsibility that the
product:
PC104-DIO48
Part Number

48-Bit Digital I/O Board
Description

to which this declaration relates, meets the essential requirements, is in conformity
with, and CE marking has been applied according to the relevant EC Directives listed
below using the relevant section of the following EC standards and other normative
documents:
EU EMC Directive 89/336/EEC: Essential requirements relating to electromagnetic
compatibility.
EU 55022 Class B: Limits and methods of measurements of radio interference
characteristics of information technology equipment.
EN 50082-1: EC generic immunity requirements.
IEC 801-2: Electrostatic discharge requirements for industrial process measurement
and control equipment.
IEC 801-3: Radiated electromagnetic field requirements for industrial process
measurements and control equipment.
IEC 801-4: Electrically fast transients for industrial process measurement and control
equipment.

Carl Haapaoja, Director of Quality Assurance

Measurement Computing Corporation
10 Commerce Way
Suite 1008
Norton, Massachusetts 02766(508) 946-5100
Fax: (508) 946-9500
E-mail: info@mccdaq.com
www.mccdaq.com