BayTech DS74 User manual

DS Series Manual
DATA SWITCH
DS74 Serial Input - Output Module
BayTech Manual Publication
Revision May 2008

DS74 Serial I/O Module
2
Copyright 2007 by Bay Technical Associates, Inc.
BayTech, is a registered trademarks of Bay Technical Associates, Inc.
Windows 2000®, Windows XP® are products and registered trademark of Microsoft Corporation.
Tera Term is a product and registered trademark of Vector, Inc.

DS74 Serial I/O Module
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Cabling............................................................................................................................................................4
RJ-45 Cables and Adapters.........................................................................................................................4
Adapters ......................................................................................................................................................5
Serial Setup.................................................................................................................................................5
Unit Configuration Menu..................................................................................................................................6
DS74 Configuration Menu...............................................................................................................................6
Status...........................................................................................................................................................7
Serial Port Configuration..............................................................................................................................7
Handshaking............................................................................................................................................7
Baud Rate................................................................................................................................................8
Word Size.................................................................................................................................................9
Stop Bits...................................................................................................................................................9
Parity........................................................................................................................................................9
RTS/DTR Line Driver Inactivity State.....................................................................................................10
Port Device Name......................................................................................................................................10
Port Device Type.......................................................................................................................................11
Verify DS74 is functioning:............................................................................................................................12
RESET DS74 Configuration..........................................................................................................................12
BayTech Product Warranty...........................................................................................................................13
Technical Support......................................................................................................................................14
Return Authorization Process:...................................................................................................................15

DS74 Serial I/O Module
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Cabling
RJ-45 Cables and Adapters
DS74 EIA-232 RJ-45 Signal
Pin EIA 232
Signal Signal Direction Description
1 DTR Out
Handshake, Line Driver Inactive State = Low: -12V when port is selected
unless programmed differently. Used as a handshake line to enable/disable
the receiving of characters.
2 GND Signal Ground
3 RTS Out
Handshake, Line Driver Inactive State = Low: -12 V when port is selected
unless programmed differently.
4 TX Out Transmit Data Out
5 RX In Receive Data In
6 DSR In
Handshake In. +12V when not used.
7 GND
Signal Ground
8 CTS In
Used as a handshake line to enable/disable the receiving of characters.
Adapters Signals
Listed are the pin specifications for the BayTech cable and adapters and the terminal COM ports:
Signal RS-232
Port (DS) RS-232 Port (RPC) COM Port DE-9 Pin COM Port DB-25 Pin Signal
DTR 1 1 4 20 DSR
GND 2 2 1 GND
RTS 3 3 7 5 CTS
TXD 4 4 3 2 RXD
RXD 5 5 2 3 TXD
DSR 6 N/C 6 6 DTR
GND 7 7 5 7 GND
CTS 8 8 4 RTS
DTR 4 DCD
DCD 8 1 8 DTR
RI 9 22

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Adapters
RJ08X007
Figures 1 and 2 provide visual representation of an RJ-45 receptacle and plug.
Serial Setup
•Connect the EIA-232 port to a Baytech device via the RJ08X007 rolled flat ribbon cable.
•Baytech makes custom cables for some devices.
•Default configuration is 9600 bps, 8 data bits, 1 stop bit and no parity.

DS74 Serial I/O Module
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Unit Configuration Menu
The configuration menu allows the user to choose which unit they would like to access. Enter the number
that corresponds with the Host Module followed by a <cr>. Now the module can be configured as shown.
This menu is where you will be able to edit any of the information listed below. The following pages define
each line of the configuration menu.
NOTE: The DS74 I/O peripheral configuration is save to the host module.
DS74 Configuration Menu
IMPORTANT: Once you make a change to any of the Configuration options, you have to back out
of the Configuration menu and will be asked to ‘Accept changes’. If you type ‘Y’ for YES, the
changes take effect immediately for the serial port.
Accept changes ? (Y/N) :y
Changes accepted.
Copyright(C) Bay Technical Associates 2005
Data Switch Series - EIA-232 I/O Module
Module 2
Status..........................1
Serial Port Configuration.......2
Port Device Name................3
Port Device Type................4
Exit............................X,CR
Enter Request :
Configuration
DS62 module #1..........1
DS74 module #2..........2
DS-RPC module #5..........3
Enter Request :

DS74 Serial I/O Module
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Status
Displays the current configuration of each I/O port.
Serial Port Configuration
Since the DS74 I/O modules use different serial port configurations. Handshaking, Baud Rate, Word Size,
Stop Bits, and Parity can all be configured through the HOST module using the menus. The default settings
are 9600bps, 8 data bits, no parity, one stop bit, RTS and DTR High.
Select 2), the peripheral module responds asking for a port number:
Type the port number, press <cr> and the unit responds:
Handshaking
For a simple communication between modems three connected lines are needed: TX, Rx, and Ground. For
the data to be transmitted, both sides have to be clocking the data at the same baud rate. While this method is
sufficient for most applications, it is limited in being able to respond to problems such as the receiver getting
overloaded. This is where serial handshaking can help.
Select 1), for the Handshaking menu, Default is None, the Host module responds with the following:
+----+------+-----------------+------+------+------+------+---------+----+----+
|Port|Device| Device | Baud | Word | Stop |Parity|Handshake|LineDrive|
| | Type | Name | Rate | Size | Bits | | |DTR |RTS |
+----+------+-----------------+------+------+------+------+---------+----+----+
| 1 | RS232| Device A | 9600 | 8 | 1 | None | None | HI | HI |
+----+------+-----------------+------+------+------+------+---------+----+----+
Handshaking......................1
Baud Rate........................2
Word Size........................3
Stop Bits........................4
Parity...........................5
RTS Line Driver Inactive State...6
DTR Line Driver Inactive State...7
Enter Request :1
Enter Serial Port Number (? = Help, ENTER = Exit) :1
+----+------+-----------------+------+------+------+------+---------+----+----+
|Port|Device| Device | Baud | Word | Stop |Parity|Handshake|LineDrive|
| | Type | Name | Rate | Size | Bits | | |DTR |RTS |
+----+------+-----------------+------+------+------+------+---------+----+----+
| 1 | RPC | Device A | 9600 | 8 | 1 | None | None | HI | HI |
+----+------+-----------------+------+------+------+------+---------+----+----+
| 2 | RS232| Device B | 9600 | 8 | 1 | None | None | HI | HI |
+----+------+-----------------+------+------+------+------+---------+----+----+
| 3 | RS232| Device C | 9600 | 8 | 1 | None | None | HI | HI |
+----+------+-----------------+------+------+------+------+---------+----+----+
| 4 | RS232| Device D | 9600 | 8 | 1 | None | None | HI | HI |
+----+------+-----------------+------+------+------+------+---------+----+----+
Strike ENTER to continue

DS74 Serial I/O Module
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Type a number to select the handshaking option and press <cr>.
1. Software Handshaking: This style uses actual data bytes as control characters. The lines necessary
are TX, Rx, and ground since the control characters are sent over the transmission line like regular
data. The two control characters, XON and XOFF are characters sent by the receiver of the data to
halt the transmitter during communication.
NOTE: A drawback to this method is also the most important fact to keep in mind. In ASCII
transmissions these character values are non-character values; however, data being transmitted via
binary, it is very likely that these values could be transmitted as data and the transmission would fail.
2. Hardware Handshaking: This style uses actual hardware lines. Like the TX and Rx lines, the
RTS/CTS and DTR/DSR lines work together. When a receiver is ready for data, it will assert the RTS
(Request to Send) line. This is then read by the sender at the CTS (Clear to Send) input, indicating it
is clear to send the data. DTR (Data Terminal Ready) and DSR (Data Set Ready) allow the serial port
and the modem to communicate their status. When the modem is ready for data to be sent, it will
assert the DTR line indicating that a connection has been made across the phone line. This is read in
through the DSR line and the modem can begin to send data. The general rule of thumb is that the
DTR/DSR lines are used to indicate that the system is ready for communication where the RTS/CTS
lines are used for individual packets of data.
Baud Rate
Select 2), Baud Rate is the rate the modem transfers Data bites per second, Default is 9600, the Host module
responds:
Type a number to select the Baud Rate and press <cr>.
Select baud rate:
1 For 300
2 For 600
3 For 1200
4 For 2400
5 For 4800
6 For 9600
7 For 19200
8 For 38400
9 For 57.6K
A For 76.8K
B For 115.2K
Enter Request :
Select handshaking:
1 For None
2 For Software Handshaking
3 For Hardware Handshaking
Enter Request :

DS74 Serial I/O Module
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Word Size
The word size is the measurement of the actual data bits in a transmission. Which setting you choose
depends on what information you are transferring. For example, standard ASCII has values from 0 to 127 (7
bits). Extended ASCII uses 0 to 255 (8 bits). If the data being transferred is simple text (standard ASCII),
sending 7 bits of data per packet is sufficient for communication. A packet refers to a single byte transfer,
including start/stop bits, data bits, and parity.
Select 3), to get the Word Size, Default is 8 the Host module responds:
Type a number to select the Word Size and press <cr>.
Stop Bits
The Stop Bits are used to signal the end of communication for a single packet. Since the data is clocked
across the lines and each device has its own clock, it is possible for the two devices to become slightly out of
sync. Therefore, the stop bits not only indicate the end of transmission but also give the computers some
room for error in the clock speeds. The more bits that are used for stop bits, the greater the lenience in
synchronizing the different clocks, but the slower the data transmission rate.
Select 4), to get the Stop Bits, Default is 1 the Host module responds:
Type a number to select the Stop Bits option and press <cr>.
Parity
Parity is a simple form of error checking used in serial communication. For even and odd parity, the serial
port will set the parity bit (the last bit after the data bits) to a value to ensure that the transmission has an
even or odd number of logic high bits. For example, if the data was 011, then for even parity, the parity bit
would be 0 to keep the number of logic high bits even. If the parity was odd, then the parity bit would be 1,
resulting in 3 logic high bits. This allows the receiving device to know the state of a bit so as to enable the
device to determine if noise is corrupting the data or if the transmitting and receiving devices' clocks are out
of sync.
With no parity selected (or defaulted), it's assumed that there are other forms of checking that will detect any
errors in transmission. No parity also usually means that the parity bit can be used for data, speeding up
transmission. In modem-to-modem communication, the type of parity is coordinated by the sending and
receiving modems before the transmission takes place.
Select stop bits:
1 For 1
2 For 1.5
3 For 2
Enter Request :
Select word size:
1 For 5
2 For 6
3 For 7
4 For 8
Enter Request :

DS74 Serial I/O Module
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Select 5), to get the Parity, Default is None the Host module responds:
Type a number to select the Parity option and press <cr>.
RTS/DTR Line Driver Inactivity State
RTS (Request to Send)/ DTR (Data Terminal Ready) is normally used in conjunction with an external
modem. With no modem the RTS and DTS default state is High.
Select 6), from the Serial Port Configuration the Host Module responds:
Select 7), from the Serial Port Configuration the Host Module responds:
Type ‘Y’ for YES or ‘N’ for NO and press <cr>.
NOTE: Once you make a change to the Serial Port Configuration options, you have to back out of
the menu and will be asked to Accept changes. If you type ‘y’ for yes, the changes take effect
immediately for the serial port.
Type ‘Y’ for YES or ‘N’ for NO and press <cr>.
Port Device Name
Select the port you want to rename, followed by a <cr>. Type the name you want to identify the port.
The unit displays the current port configuration.
Accept changes ? (Y/N) :y
Enter Serial Port Number (? = Help, ENTER = Exit) :1
Changes accepted.
DTR Line Driver Inactive State is: High
High ? (Y/N, CR for no change):
RTS Line Driver Inactive State is: High
High ? (Y/N, CR for no change):
Select parity:
1 For None
2 For Even
3 For Odd
Enter Request :