User Instructions for
the USB-331 & USB-335 "SmartPipe"™ Protocol Converters

FEDERAL COMMUNICATIONS COMMISSION

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense.

CE

This equipment has been tested and found to conform to the directives and standards for a Class A Information Technology Equipment type and for the Commercial and Light Industrial equipment class.

INTRODUCTION

The USB-331 "SmartPipe"™ protocol converters change RS-232 data to standard USB keyboard signals so it can be fed directly into a any USB port, either directly or via a user supplied hub. If the PC is equipped with standard PS/2 keyboard port, a PS/2 keyboard can also be connected to the PC and will be merged with the RS-232 data. Similiary, an USB keyboard can be connected to any USB port. The connection of a keyboard is optional and not necessary for the USB-331 to operate. The USB-331 is powered from the USB port and does not need an external power supply. The USB port makes it possible to use the Converters with any computer with an USB port, such as PC's and MAC's.

The USB-335 "SmartPipe"™ protocol converters perform the same operations as the USB-331 but also includes a 2 port hub on board allowing the user to plug in other USB devices into it.

PREPARE FOR OPERATION

There are three steps to prepare the Converters for operation.

ALL CONNECTIONS SHOULD BE MADE WITH THE PC POWER OFF !!

1. Selection of baud rate: Set the baud rate using configuration DIP switch "SW1", which is located at one end of the converter, next to the DB-9 pin connector. A selection of six different baud rates is available - 19200, 9600 (factory setting), 4800, 2400, 1200, and 300. To change the factory setting of 9600 baud, use switches 1, 2, and 3 of SW1 as shown in the Baud Rate Selection diagram to set a new baud rate. For a new baud rate to take effect, the converter must be powered off and then powered on again.

2. Connect the Computer: Use the Type A-B USB cable supplied with the Converter to connect the Converter to an USB port. The converter is powered from the USB port via this cable.

3. Connect the RS-232 device: Use an appropriate cable to make this connection. A female DB-9 connector on the cable is needed to connect to the Converter. The Converter accepts (receives) RS-232 data on pin 2. The table shows the pins used by the Converter. See Data Throughput discussion below to determine if you need to connect and use the CTS (Clear To Send) signal.

Pin	Function
2	Converter receives data on this pin
5	Ground
7	CTS - Clear To Send. The Converter controls this pin to indicate when RS-232 data can be sent to it. The PC may inhibit keystroke reception. The Converter then makes this pin inactive. No data should be sent to the Converter unless this pin is active. Data is lost otherwise

The DATA FORMAT accepted by the Converters is one start bit, eight (8) data bits, least significant bit first, one stop bit, no parity.

OPERATION

The Converters accept ASCII codes on their RS-232 input, which is a male DB-9 connector. The Converters then change these codes into equivalent USB keyboard scan codes and output the scan codes on the USB connector marked "TO PC USB PORT". In this fashion, ASCII-coded RS-232 devices can be used to input keyboard data to any computer equipped with an USB port. The conversion of ASCII codes to equivalent USB keyboard keystrokes is shown in the ASCII to Keyboard Conversion Table, using standard PC keyboard keycap symbols.

Data Throughput

The USB limits keyboard data input rate to about 300 characters/sec. Mixed shifted (upper case) and Unshifted (lower case) charcaters further reduce the input rate. The USB input rates are slower than possible RS-232 ASCII character input rate, especially at higher buad rates. At 9600 buad, it is possible to send 960 charcater/sec, and at 19,200, 1920 characters/sec. The converter provides a 64 byte buffer, but unless CTS is obeyed, the maximum number of characters that can be sent without loss is limited. In addition, ASCII characters that require a PC shift for proper representation, require the simulation of the Shift key, introducing additional delay. The table below gives maximum burst sizes in ASCII characters that can be sent without loss under the best of conditions. Caution is needed in using the data from the table, since certain PC applications can be quite slow in accepting keyboard data. In such cases, the burst sizes will be less than given in the table. The table should be used only as a guide in estimating whether CTS should be used to assure data integrity.

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

0

Space

0

@

P

'

p

C/A/D

F1

Num Lock

Num Enter

Insert

LFTWIN

1

!

1

A

Q

a

q

M LCNT

B LCNT

F2

Caps Lock

Num /

Home

RTWIN

2

"

2

B

R

b

r

M LSHF

B LSHF

F3

Scroll Lock

Num *

End

WINAPP

3

#

3

C

S

c

s

M LALT

B LALT

F4

Num 9

Page Up

4

$

4

D

T

d

t

M RCNT

B RCNT

F5

Num 8

Page Down

5

%

5

E

U

e

u

M RSHF

B RSHF

F6

Num 7

Up Arrow

6

&

6

F

V

f

v

M RALT

B RALT

F7

Num 6

Down Arrow

7

`

7

G

W

g

w

M SCLK

B SCLK

F8

Num 5

Left Arrow

8

BS

(

8

H

X

h

x

F9

Num 4

Right Arrow

9

Tab

)

9

I

Y

i

y

F10

Num 3

Print Screen

A

*

:

J

Z

j

z

F11

Num 2

Pause Break

B

Esc

+

;

K

[

k

{

F12

Num 1

Del

C

,

<

L

\

l

|

Num 0

D

Enter

-

=

M

]

m

}

Num -

E

.

>

N

^

n

~

Num +

F

/

?

O

_

o

Num .

1. Blank Table entries indicate no output. 2. M - make code only (simulates "stuck" key); B - break code only (releases "stuck" key) 3. C/A/D - results in soft reset combination: Control/Alt/Delete. 4. LCNT/RCNT - left/right control keys; LSHF/RSHF - left/right shift keys; LALT/RALT - left/right Alt keys; NUM LK - Num Lock key; CAP LK - Caps Lock Key; SCROLL LK - Scroll Lock key. 5. NUM prefix denotes keys from NUM pad. 6. PRT SCR is Print Screen key. 7. LFTWIN, RTWIN, WINAPP are the Windows 95 keys. 8. Keys are specified by US English keyboard keycap legends.

The Vetra USB-331 and USB-335 Protocol Converters use technology covered by US Patent 7,299,309

Copyright © 2004 - 2007 by Vetra Systems Corporation, All Rights Reserved, Printed in U.S.A.

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VETRA Systems Corporation 275-J Marcus Blvd. Hauppauge, NY 11787 USA Toll Free 1-800-537-9296 Tel: 631-434-3185 Fax: 631-434-3516 e-mail: sales@vetra.com