Model 109A - Bidirectional Parallel-Serial Converter-Buffer
Reference Manual


Table of Contents

Overview
Features
Installation
Default Configuration
DIP Switch Settings
Cabling
Operation
Appendix
Troubleshooting
Specifications
RS-232C Interface Specification
Centronics Interface Specification
Centronics Interface Timing Chart
Preventing Radio & TV Interference
Warranty



Overview

The MODEL 109A is an interface converter that allows Centronics and RS-232 devices to communicate with each other (a computer with an RS-232 output to a Centronics printer, for example).

The unit is bi-directional enabling you to convert from serial to parallel to serial. It is configured with 512 KB of memory allowing it to serve as a printer buffer.

These two way converters provide a DB-25 RS-232C (DCE) compatible connector, and a C-36 Centronics connector. The serial baud rate is from 1200 to 115200 bps. (selectable by DIP Switch). The parallel interface speed for the (buffered) Model 109A is 1.5 MB/sec.

The units support both hardware and software (XON/XOFF) handshaking. Setup is extremely easy. All that is involved is setting the DIP Switch and connecting the cables.

Features

Parity:

DIP Switch Segment

Parity

6

7

ON

Either

Parity Inhibit

OFF

ON

Even Parity

OFF

OFF

Odd Parity

 Conversion Direction:

DIP Switch Segment 8

Conversion Direction

ON

Parallel to Serial

OFF

Serial to Parallel


Cabling
Serial to Parallel:

When performing a Serial to Parallel interface conversion:

1. Plug the female end of a 25/9-pin to 25/9-pin male/female serial cable into the PC's serial port.

2. Plug the male end of the 25-pin to 25-pin male/female serial cable into the Model 109A's serial connector.

3. Plug the female end of a C-36 to C-36 male/female printer cable into the MODEL 109A's printer connector.

4. Plug the male end of the C-36 to C-36 male/female printer cable into the printer.
Note: If your serial cable is long enough, you can plug the MODEL 109A directly into the printer without the need for a printer cable.

5. Plug the Power Adapter into an AC source; plug the Power Adapter cable into the Model 109A's power jack.

Parallel to Serial

When performing a Parallel to Serial interface conversion:

1. Plug the male end of a 25-pin (male) to C-36 (female) printer cable into the PC's parallel port.

2. Plug the female end of the 25-pin to C-36 male/female printer cable into the Model 109A's Centronics connector.

3. Plug the male end of a 25-pin to 25-pin male/female serial cable into the MODEL 109A's serial cable.

4. Plug the female end of the 25-pin to 25-pin male/female serial cable into the printer's serial port.

5. Plug the Power Adapter into an AC source; plug the Power Adapter cable into the MODEL 109A's power jack.

Serial Port Cabling

Device Connectors Pin #

 

Cables

a 25-pin/25-pin cable or a 9-pin/25-pin cable

Model 109A

DCE

DB-9

DTE

DB-9

DCE

DB-25

DTE

DB-25

 

DCE

DB-25

 

2

3

3

2

 

TX

RX

2

3

2

2

3

 

RX

TX

3

8

7

5

4

 

RTS

CTS

4

7

8

4

5

 

CTS

RTS

5

4

6

20

6

 

DSR

DTR

6

6

4

6

20

 

DTR

DSR

20

5

5

7

7

 

GND

GND

7



Parallel Port Cabling

Devices Pin #

a 25-pin/36-pin Cables

or a 36-pin/36-pin Cable

MODEL 109A

DB-25

C-36

C-36

1

1

STROBE

1

2-9

2-9

D0-D7 

2-9

10

10

ACK

10

11

11

BUSY

11

12

12

PE

12

13

13

SLCT

13

14

14

AUTOFEED XT

14

15

32

ERROR

32

16

31

INIT

31

17

36

SLCT IN

36

18-25

19-30

GND

19-30



Operation

When operating the MODEL 109A, please take note of the following:

1. Since the MODEL 109A is a DCE device, the serial device it connects to must be configured as a DTE device.

2. In DCE mode, the unit uses RTS/DTR (pins 5 and 6) handshaking. When RTS/DTR is at +9V, the computer is allowed to transmit data. When the unit is busy, it sets the RTS/DTR link to -9V, and the computer stops transmitting data. Consequently, if the computer can not identify the RTS/DTR signal, it may result in data loss.

3. The unit is powered by the host RS-232C interface. In addition to the TxD line, it is recommended that the host RS-232C interface (MC 1488, SN 75188, or equivalent IC's), also support RTS and DTR lines, which provide a power source above 9V, to ensure normal operation of the unit.

4. The unit's baud rate, data length, stop bits and parity settings must be configured to match those of the computer.

5. You must reset the parallel printer before printing.

Appendix
Troubleshooting

Problem Cause

Solution

Power LED does not light

Unit is not receiving power.

Make sure that there is no problem with the AC source, and that the AC adapter is fully operational.

Make sure that the adapter is correctly plugged into the AC source and that the cable is fully plugged into the units power jack.

No Data

Transmission

Cables are not properly plugged in.

Make sure that all cables are properly plugged in and fully seated in their connectors.

Cables are not properly wired.

Rewire the cables making sure they are correctly wired.

Transmitting or Terminal device has not been set Ready for data transfer.

If powered Off, turn the device On.  Otherwise, reset the Transmitting or Terminal device.

Transmitting or Terminal device is incorrect DTE mode.

Rewire the cable lines to be sure they are properly connected.

Incorrect Data

Received

Lines are not properly connected

Rewire the cable lines to be sure they are properly connected.

Incorrect serial transmission DIP Switch settings.

Set the DIP switch segments to their proper setting.



If the above solutions fail to alleviate the problem, contact your dealer for help.

RS-232C Interface Specification

The RS-232C Interface DCE mode (default) specifications is given in the table below:

Pin

Name

Function

1

Ground

Ground

2

RxD

Receive Data

3

TxD

Transmit Data

4

CTS

Clear to Send

5

RTS

Request to Send

6

DTR

Data Terminal Ready

7

Ground

Ground

8

CD

Pull Up (+9V)

20

DSR

Data Set Ready


Centronics Interface Specifications
The Centronics Interface Specification is given in the table below:

Pin

Name

Function

1

STB

DATA STROBE

2

DATA BIT 1

DATA BUS

3

DATA BIT 2

4

DATA BIT 3

5

DATA BIT 4

6

DATA BIT 5

7

DATA BIT 6

8

DATA BIT 7

9

DATA BIT 8

10

ACK

DATA RECEIVED KNOWLEDGE

11

BUSY

DEVICE BUSY OR NOT

12

PAPER EMPTY

PULL UP

13

SLCT

PULL UP

14

A-F

PULL UP

15

N.C.

 

16-17

GROUND

GROUND

18

N.C.

 

19-30

GROUND

GROUND

31

INIT

PULL UP

32

ERR

PULL UP

33

GROUND

GROUND

34-35

N.C.

 

36

SL-1

PULL DOWN



Specifications:

Power Consumption

AC 9V 150m A (max.)

Cable Distance

Up to 9m (30)

Connectors

RS-232C

DB-25 female DCE

Centronics

C-36 male

Memory Size

512 KB

Interface Exchange

In

Serial to Parallel

Out

Parallel to Serial

Serial Communications Mode

DCE Only

LEDs

Power (Green)

Microcontroller

ASIC

Function Key

Reset

Buffer Speed

Serial

1200 115200 bps

Parallel

1.5 MB/sec. (max.)

Data Compression

8.5:1 (max.)

Temperature

Operating

5 - 40 C

Storage

-20 - 60 C

Humidity

0 80%

Housing

Plastic

Weight

120 g

Dimensions (LxWxH)

101 x 62 x 25.5 mm



Radio & TV Interference

Warning. This equipment generates, uses and radiates radio frequency energy and if not installed and used in accordance with the instruction manual may cause interference to radio and television reception. It has been tested and found to comply with the limits for a Class A computing device in accordance with the specifications in Subpart J of Part 15 of the FCC Rules, which are designed to provide reasonable protection against such interference when operated in a commercial environment. Operation of this equipment in a residential area is likely to cause interference, in which case the user at his own expense will be required to take whatever measures may be required to correct the interference.

If this equipment does cause interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures.

1. Reorient the receiving antenna.

2. Relocate the computer with respect to the receiver.

3. Move the computer away from the receiver.

4. Plug the computer into a different outlet so that the computer and receiver are on different branch circuits.

5. Ensure that the mounting screws, attachment connector screws and ground wire are tightly secured.

6. Ensure that good quality shielded and grounded cables are used for data communications.

If necessary, the user should consult the dealer or an experienced radio/television technician for additional suggestions.

Limited Warranty

IN NO EVENT SHALL THE DIRECT VENDOR'S LIABILITY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES RESULTING FROM THE USE OF THE PRODUCT, DISK, OR ITS DOCUMENTATION EXCEED THE PRICE PAID FOR THE PRODUCT.

The direct vendor makes no warranty or representation, expressed, implied, or statutory with respect to the contents or use of this documentation, and especially disclaims its quality, performance, merchantability, or fitness for any particular purpose. direct vendor also reserves the right to revise or update the device or documentation wit The hout obligation to notify any individual or entity of such revisions, or update. For further inquiries, please contact your direct vendor.

Document No. 0315-0324/rev -

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