Smart Switch Model 232SS2 Document No. 232SS21600 This product Designed and Manufactured of domestic and imported parts by International Headquarters B&B Electronics Mfg. Co. Inc. 707 Dayton Road -- P.O. Box 1040 -- Ottawa, IL 61350 USA Phone (815) 433-5100 -- General Fax (815) 433-5105 Home Page: www.bb-elec.com Sales e-mail: orders@bb.elec.com -- Fax (815) 433-5109 support@bb.elec.
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TABLE OF CONTENTS Chapter 1: INTRODUCTION...............................................1 Checklist.................................................................................2 Chapter 2: SETUP ...............................................................3 Port Configuration ..................................................................4 Serial Data Configuration .......................................................5 Smart Switch Operation .......................................................
Chapter 1: INTRODUCTION The RS-232 Four Port Smart Switch/Port Combiner, Model 232SS2, allows one RS-232 host device to connect to as many as four RS-232 devices. The switch can be controlled in two different ways. The first way is referred to as smart switch mode. In this mode, the switch is controlled by sending a programmable preamble code to the "Master" port of the 232SS2. The other way the switch can be controlled is referred to as port combiner mode.
Checklist Examine the shipping carton and contents for physical damage. If damage is found, file a claim with the shipper immediately. The following equipment should be in the shipping carton: 1. RS-232 Smart Switch 2. Instruction Manual 3. (2) 3.5" floppy disks If any of the items above are not in the shipping carton contact the shipper immediately.
Chapter 2: SETUP The 232SS2 is set up using an eight-position dipswitch. This dipswitch is used to set the communication format, port configuration, smart switch/port combiner mode and to enable/disable the enhanced features. To change the settings on the switch, remove the power from the unit, and remove the screws (2) from the bottom of the 232SS2. The dipswitch is located on the top of the PC board (side with LEDs) and is labeled “SW1.
Port Configuration In order to determine the proper port configuration of the 232SS2, it is necessary to have a basic understanding of the terms DCE and DTE. RS-232 was designed, using DB-25 connectors, for connecting a DTE (Data Terminal Equipment) device to a DCE (Data Communication Equipment) device. Each device will have inputs on pins that correspond to outputs on the same pins of the other device.
Table 2. DCE MASTER PORT CHART Master Port A,B,C & D Ports (DCE) Signal (DTE) Pin# Direction Description Pin# Direction 2 Input Transmit Data (TD) 2 Output 3 Output Receive Data (RD) 3 Input 4 Input Request to Send (RTS) 4 Output 5 Output Clear to Send (CTS) 5 Input 6 Input DCE Ready (DSR) 6 Output 7 GROUND Signal Ground (SG) 7 GROUND 8 Output Recv. Line Detect (DCD) 8 Input 20 Input DTE Ready (DTR) 20 Output Table 3.
Switch position 8 selects the port configuration, see section titled "Port Configuration". Refer to Table 1. Always power down the smart switch when changing switch settings. Smart Switch Operation Smart Switch mode is selected when dipswitch “SW1” position 7 is “Off.” In Smart Switch mode, the 232SS2 is constantly looking for the three character preamble code by monitoring the data that is being received on the master port from the host device.
Programming the Second Character The second character comes programmed as the ASCII STX character (decimal 2). You can change this to any 8-bit character you wish by reprogramming dipswitch “SW2”. “SW2” is an eightposition switch with each position equal to a certain weight. Refer to “Setup” for instructions on removing the cover to access “SW2”. Table 4 shows the weight chart for “SW2”. Table 4.
Smart Switch/Port Combiner Mode This mode allow Ports A-D to select the master port using a handshake line. It also allows selection from the master port via the preamble code described in the Smart Switch Only Mode section. Position 7 of “SW1” must be ON to be in port combiner mode. When a handshake line goes high on any of the four ports, it will establish a connection from that port to the master port. This works on firstcome-first-serve basis.
A typical application would be to have RTS and CTS tied together on the master port. When RTS (assuming DTE slave device) on port A (configured as DCE) is asserted, CTS on port A will be asserted when a connection is established. If a port is not connected to the master port, then CTS on that port will remain low. Therefore, a port can monitor the handshake line to determine if a connection has been established.
Table 3 - Timer Values Data Byte Value 0 1 2 3 4 5 6 7 8 9 timer disabled 10ms 25ms 100ms 500ms 1s 5s 30 s 1 min. 5 min. The Set Timer Mode command requires the third byte to be an ASCII “M”. If the data byte (fourth byte) is an ASCII “0”, zero (default), the timer will be setup as an inactivity timer. For example: Sending the following string to the 232SS2 will set up the timer as an inactivity timer (assuming programmable character is the factory default of 2).
The “M” tells the 232SS2 it is the set timer mode command and the “1” indicates to set up the timer to ignore switching commands. When the timer is configured in this mode, the 232SS2 will not accept any switching commands (“A”, ”B”, ”C”, ”D”, or “EOT”) for the specified timer value. After the timer has expired, the slave port that is connected to the master port will be disconnected. This feature is useful to prevent inadvertent switching during binary/graphic type file transfers.
Chapter 3: SOFTWARE Introduction The 232M`SS2 comes with two application programs that can be used to switch between ports. Each comes on a separate floppy disk. Either can be used independently as the final application or for testing the functionality of the hardware. The SSwitch program is a Windows program that allows you to switch ports with buttons on a Windows interface, or from the DOS command line. It will run on Windows 95, 98, or Windows NT 4.0 with service pack 3 installed.
To Uninstall SSwitch.exe • • • • From START/ SETTINGS/ CONTROL PANEL Select Add/ Remove Programs Select SSwitch from the list of programs Click on the Add/Remove button DOS SSTSR Installation To Install the SSTSR Program (DOS) If A drive is your floppy drive: • • • Place the Smart Switch for DOS disk in drive A At the DOS prompt Type a:\INSTALL.exe and press the ENTER key. The following files will be located on your hard drive: 1)SSTSR.EXE - The executable file for the Smart Switch. 2)SETUP.
Enter Port Address [02F8]: Enter Baud Rate ( 1 = 150 2 = 300 3 = 600 4 = 1200 5 = 24006 = 4800 7 = 9600 8 = 19200) [7]: Enter Parity (0 = No 1 = Odd 2 = Even) [0]: Enter Number of Data Bits ( 7 = Seven Data Bits 8 = Eight Data Bits) [8]: Enter Smart Switch Second Char (Decimal Value) [2]: Enter Hot Key Sequence (1 = 2 = 3 = <1|2|3|4|N> 4 = <1|2|3|4|N> 5 = 6 =<1|2|3|4|N>)[1]: At this point
If the software was installed in the default directory: • At the DOS prompt Type C: and press the ENTER key. • Type CD\232MSS2 and press the ENTER key. To begin the SSTSR program (the following will be used as an example): Port Address = 03F8 Parity = Odd Baud = 9600 User Defined Char. = 8 Data Bits = 8 Hot Key Sequence = 4 • Type SSTSR A03F8 B7 D8 P1 U8 H6 and press the ENTER key.
The Hot Key is a sequence of three keys that must be pressed simultaneously to switch from one Smart Switch Port to another. For example, the hot key sequence, states that the left shift, Alt, and either A, B, C, D, or N must be pressed at the same time to select the corresponding Smart Switch Port. N turns off all Smart Switch ports.
Hot Key Method This method enables the user to select any Smart Switch port by pressing a predefined sequence of keys at the same time after the SSTSR is installed (refer to Program Installation). Example: If Hot Key sequence was selected, to change ports you would press at the same time: Left Shift - Alt - A ..... to select port A Left Shift - Alt - B ..... to select port B Left Shift - Alt - C ..... to select port C Left Shift - Alt - D .....
APPENDIX A: ASCII Character Codes DECIMAL to HEX to ASCII CONVERSION TABLE DEC HEX ASCII KEY DEC HEX ASCII DEC HEX ASCII DEC HEX ASCII 0 0 NUL ctrl @ 32 20 SP 64 40 @ 96 60 ` 1 1 SOH ctrl A 33 21 ! 65 41 A 97 61 a 2 2 STX ctrl B 34 22 “ 66 42 B 98 62 b 3 3 ETX ctrl C 35 23 # 67 43 C 99 63 c 4 4 EOT ctrl D 36 24 $ 68 44 D 100 64 d 5 5 ENQ ctrl E 37 25 % 69 45 E 101 65 e 6 6 ACK ctrl F 38 26 & 70 46 F 102 66 f 7 7 BEL
APPENDIX B: Cable Charts All charts will indicate if the Master Port of the 232SS2 should be configured as a DCE port or a DTE port. Refer to the Port Configuration section of the manual for information on Master Port configurations. Chart 1.
Chart 3. Modem DB25 Connector to Master Port Straight Through Connection Async Modem Serial Port DB25 Connector 2 3 4 5 7 8 20 Signal Direction <---------------------> <---------------------> GROUND -----------> <----------- 232SS2 Master Port (DTE) DB25 Connector 2 3 4 5 7 8 20 Chart 4. IBM PC DB25 Connector to Ports A - D (DTE) Master port DCE, Slave port DTE.
Chart 5. IBM PC DB25 Connector to Ports A - D (DCE) Master port DTE, Slave ports DCE. Straight Through Connection IBM PC Serial Port DB25 Connector 2 3 4 5 6 7 8 20 Signal Direction -----------> <---------------------> <----------<----------GROUND <---------------------> 232SS2 Ports A - D (DCE) DB25 Connector 2 3 4 5 6 7 8 20 . Chart 6. IBM PC DB9 Connector to Ports A - D (DTE) Master port DCE, Slave port DTE.
Chart 7. IBM PC DB9 Connector to Ports A - D (DCE) Master port DTE, Slave port DCE.
FEDERAL COMMUNICATIONS COMMISSION RADIO FREQUENCY INTERFACE STATEMENT Class A Equipment This equipment has been tested and found to comply with the limits for 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.
