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Rabbit EM1500 Product Manual

Industrial grade serial-to-ethernet converter and modem
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EM1500 User's Manual
019-0124 • 070720-E
The latest revision of this manual is available on the Rabbit Semiconductor Web
site, www.rabbit.com, for free, unregistered download.

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Summary of Contents for Rabbit EM1500

  • Page 1 EM1500 User’s Manual 019-0124 • 070720-E The latest revision of this manual is available on the Rabbit Semiconductor Web site, www.rabbit.com, for free, unregistered download.
  • Page 2 These copies of the manuals may not be let or sold for any reason without the express written permission of Rabbit Semiconductor. Rabbit Semiconductor reserves the right to make changes and improvements to its products without providing notice. Trademarks ®...

  • Page 3: Table Of Contents

    2.2.2 Making the Connection ..........................15 2.3 Using the Demo Board ............................. 15 2.3.1 Select an EM1500 ............................ 15 2.3.2 Wiring the Demo Board to the Selected EM1500 ..................16 2.3.3 Digital Output ............................16 2.3.4 Digital Input and Relay ..........................17 Chapter 3 Assigning an IP Address to the EM1500 3.1 How to Obtain an IP Address ...........................
  • Page 4 Appendix A EM1500 Specifications A.1 Mechanical Characteristics..........................77 A.1.1 Base Plate ..............................78 A.2 Specification Table............................79 A.3 EM1500 EMI / EMC Information........................80 A.3.1 CE Compliance ............................80 A.3.2 EM1500 FCC Compliance ........................82 A.4 EM1500 Jumpers.............................. 83 A.4.1 How to Access the Jumpers ........................83 A.4.2 How to Move the Jumpers ........................84...

  • Page 5: Chapter 1 Introduction

    "modem control" signals. The EM1500 has 5 serial ports. It has 4 RS232 serial ports, and a half-duplex RS485 port, all of which may be connected to different remote TCP/IP hosts. That is to say, each serial port may connect over the Internet, or a local Ethernet LAN, to a single host at any one time;...

  • Page 6: Summary Of Features

    1.2 Summary of Features Physically and functionally the EM1500 is a black box. As any good black box should be, the EM1500 is simple to use. No programming is needed. The tight integration of hardware and software offers unparal- leled reliability. Quick configuration over Ethernet, using a web browser or the stand-alone configuration program, is easy and convenient.

  • Page 7: Hardware Highlights

    3 digital inputs (IN0-2) on 9-pin header, suitable for interfacing to mechanical switches or logic level circuits • SPDT relay contacts, allows EM1500 to cycle power to attached device, or to switch other signals • 4 status LEDs Power, Link, Active and User •...

  • Page 8: Software Highlights

    • RFC2217 + Rabbit extensions for packetized data and for two EM1500s communicating with each other. Extensions are transparently negotiated. • EM1500 can be 'server' and/or 'client' (server only for RFC2217 protocol) • Connections can be actively opened (client mode) based on modem line conditions, on received characters, on ATD type commands, or unconditionally.
  • Page 9 • based on open source GUI toolkit (FOX). • relatively easy for OEMs to customize • EM1500 may be configured to require encrypted configuration updates. These are sup- ported by the stand-alone program. Subject to U.S. export restrictions. • EM1500s can be automatically “discovered” on the local Ethernet segment.

  • Page 10: Em1500 Factory Defaults

    1.2.3 EM1500 Factory Defaults Every EM1500 is shipped with default values for some of the configuration parameters already set. Some parameters have been left blank where it makes no sense to have a default, such as the IP address and net- mask for the unit.
  • Page 11 Table 1-3. EM1500 Default Configuration Parameters Configuration Configuration Parameter Default Setting Category SER1-8888, SER2-8889, SER3-8890 Local TCP port SER4-8891, RS485-8892 Remote TCP port same as local TCP port Ephemeral port ON (all serial ports) Use Nagle ON (all serial ports) Don’t Purge...

  • Page 12: The Em1500 And Its Tool Kit

    The EM1500 ships without cables, power or documentation. All cables, etc., for use with the unit are pack- aged in the EM1500 Tool Kit, which may be purchased separately. The cables in the Tool Kit may also be puchased separately using the part numbers shown in the table below. Initially you will probably want to purchase a Tool Kit.

  • Page 13: Rabbit Engineering Demo Board

    Section 2.3 for some tips on how to use it. 1.5 Contact Information If you purchased your EM1500 through a distributor or Rabbit Semiconductor partner, contact the distribu- tor or Rabbit partner first for technical support. To contact Rabbit Semiconductor: •...
  • Page 14 www.rabbit.com Introduction...

  • Page 15: Chapter 2 Getting Started

    EM1500 explicitly knowing the IP address of the host PC. This is because the EM1500 will not be initiating the Ethernet connection in these 2 cases. This is not to say that the host PC does not need an IP address—it definitely does. How this is accomplished depends on the operating system and the network card that is installed on the machine.

  • Page 16: Power Supply

    2.1.1.3 Using a Hub and Two Straight-Through Cables The Ethernet connection does not have to be direct. The EM1500 and the host PC may be connected to the same LAN through a hub. This way has the benefit of allowing more than one EM1500 unit to be config- ured in the same configuration session.

  • Page 17: Up And Running

    Open emconf or emconf.exe. This program will try and discover any EM1500s that reside on the same LAN as the host PC. You should be able to see the EM1500 on the upper left side of the program window. Click on its icon; this highlights the entry and shows status information for the unit in the area below its selection.
  • Page 18 If using DHCP did not result in an IP address being assigned to the EM1500, you will need to assign one manually. First, get an IP address from your network administrator. Now, click on the Network tab and type in the IP address in the first field of the Net- work dialog.

  • Page 19: Making The Connection

    Open emconf or emconf.exe. As explained in the previous section, this program will try and discover any EM1500s that reside on the same LAN as the host PC. You should be able to see the EM1500 on the upper left side of the program window. Click on its icon; this highlights the entry and shows status infor- mation for the unit in the area below its selection.

  • Page 20: Wiring The Demo Board To The Selected Em1500

    (screw terminal) on the EM1500. input 2. Use a single wire to connect GND from the Demo Board to GND (screw terminal) on the EM1500. 3. Connect the 9-wire assembly with plug that came with the Tool Kit to the 9-pin connector on the EM1500.

  • Page 21: Digital Input And Relay

    When the relay is closed, contact is made with the normally open pole; therefore, pressing SW1(i.e., completing the circuit) causes the state of IN1 to change, which is then reflected in the button color for IN1. www.rabbit.com EM1500 User’s Manual...
  • Page 22 www.rabbit.com Getting Started...

  • Page 23: Chapter 3 Assigning An Ip Address To The Em1500

    3.1 How to Obtain an IP Address There are two ways to obtain a valid IP address for the EM1500. One is through dynamic assignment using DHCP/BOOTP. The EM1500 is a DHCP client by default. If a DHCP server resides on the same LAN as the EM1500, an IP address will be assigned to the EM1500 when it is powered on.

  • Page 24: Directed Ping

    The six digits are identified by “MAC ID:” The EM1500 must be on the same LAN as the host machine from which you issue the following ARP and ping commands.

  • Page 25: Chapter 4 Em1500 Specifics

    4. EM1500 S PECIFICS This chapter describes the front and back panels of the EM1500 and in particular the pin-outs for the serial ports and the jumpers for changing their default behavior. 4.1 Front Panel of EM1500 On the front panel are connectors for Ethernet, RS-485 and power. There is also a reset button, LEDs, and a label containing the last six digits of the unit’s...

  • Page 26: User Led Patterns

    The User LED on the front panel is a bi-color LED. It has a red and a green chip within, which provides a total of four states: off, red, green and orange. It indicates the overall status of the EM1500 as follows: Table 4.2 User LED Patterns...

  • Page 27: Back Panel Of Em1500

    4.2 Back Panel of EM1500 The connectors on the back panel are shown in the following figure. Please note that pin 1 is PF2 on the 2x5 IDC header. Figure 4.2 Back Panel of EM1500 SER 2 / RS-232 DE9 F...

  • Page 28: Connector Pin-Outs

    The serial port known as SER2 is wired as a DCE with a DE9 female connector. It is located at the upper right on the rear of the unit. The figure below shows the pin-out. The black circles denote outputs. The white circles denote inputs. Figure 4.4 Pin-Out for SER2 www.rabbit.com EM1500 Specifics...

  • Page 29: Serial Port 3 And 4 (Ser3 & Ser4)

    Serial ports SER3 and SER4 are available on the 2x5 IDC header (aka, the 10-pin header) on the back panel of the EM1500. By default, they are both 3-wire ports at RS-232 levels. Both can be jumpered for TTL level signals. SER3 is also configurable as a 5-wire RS-232 or TTL level port or a 9-wire port at TTL levels.

  • Page 30: Serial Port 5 (Rs485)

    The EM1500 can be used in an RS-485 multidrop network spanning up to 1200 m (4000 ft), and there can be as many as 32 attached devices. Connect the 485+ to 485+ and 485– to 485– using single twisted-pair wires as shown in the figure below.
  • Page 31 A slave can only transmit when the master has given it express permission to do so. The EM1500 should be used as the master. All other nodes should be configured as slaves in the sense that they only transmit when specifically addressed by the EM1500 that is acting as master.
  • Page 32 Rabbit extensions: yes (required for packetiza- tion support) Packetizing: Idle Idle time units: byte Rx idle time: 4 (rounded up from 3.5) Tx idle time: 4 (rounded up from 3.5) Max buffer: 1020 Trailing chars: 0 www.rabbit.com EM1500 Specifics...
  • Page 33 Serial:Rx idle time amount to the same thing (and the maximum of both is used). From the point of view of one half of the complete connection, i.e. a single EM1500 with an RS485 port on one side and the network on the other, the following situation obtains: On the network side, packets are received for later transmission out the RS485 port.

  • Page 34: 9-Pin Connector

    TTL levels. PF0-4 have 470 ohm series resistor protection , which allows them to tolerate RS232-level signals. However, the loading of the RS232 input signal may be too high for some equipment. Internally, the connection is terminated by diode clamps to GND and Vcc (3.3 V). www.rabbit.com EM1500 Specifics...

  • Page 35: Chapter 5 Em1500 Configuration

    Linux users and emcomf.exe for Windows) will be used for this purpose. Both versions of the configuration utility are on the CD that comes with the EM1500 Tool Kit. The information contained in this chapter is also useful for someone using a web browser for configuration since the user interface for both methods have a similar organization (with some differences) and identical terminology.
  • Page 36 Protocol - This dialog displays advanced options. Choose View | Advanced from the main menu if you can not see this tab when you run emconf. This is where you may enable the EM1500 to be a RFC2217 modem server, as well as make it compatible with the use of a PC COM port redirector that complies with RFC2217.
  • Page 37 Now press <Ctrl+C> to copy the selected configuration to the clipboard; select an EM1500 entry (another single click) and press <Ctrl+V> to paste the configuration from default.emc to the EM1500. Other file operations (i.e., Open, Save, Close, etc.) may be performed on the configuration database entries, but not the...

  • Page 38: General Tab

    The unit name is a text string chosen by the user to uniquely identify the unit. It may be left blank if the unit is unnamed. A unit’s name will be displayed in the listbox on the left side of the program window if the EM1500 responded during discovery. Domain name This is the name of the unit.
  • Page 39 Routers This is where you specify the IP addresses of the routers that the EM1500 will use when packets need to be forwarded outside of the LAN. For most cases enter just the IP address of the router in dotted decimal form and leave the mask and network entries zero.
  • Page 40 .foxrc. In this directory, a subdirectory for Rabbit products will be created. Under this directory will be a file with registry settings for the emconf application, called EM1500. Thus, the settings for each user are contained in the file ~/.foxrc/Rabbit/EM1500...
  • Page 41 Even so, a critical evaluation of risk should be taken before the EM1500 is used in the field. The security offered by secure configuration is only as good as the degree of protec- tion afforded to the key file on the PC.

  • Page 42: Aux I/O Tab

    This parameter controls the initial state of the SPDT relay on boot-up. It may be open or closed. The relay may be used to cycle power on an attached device. Note that the relay is non-latching. When the EM1500 is powered off the relay will always be “open.”...
  • Page 43 9-pin connector. The default state is “pulled up.” To change the state to “pull-down” means moving the zero ohm resistor at JP1, which will require some soldering. For directions on how to access JP1, please see A.4, “EM1500 Jumpers.” www.rabbit.com EM1500 User’s Manual...

  • Page 44: Network Tab

    This screen has information about the Ethernet interface. Most importantly, this is where you may assign a known IP address to the EM1500. If you are using DHCP, an IP address entered here will be used as a backup if the DHCP attempt fails.
  • Page 45 EM1500 for the unit to succeed as a DHCP client. This option is enabled by default. If your EM1500 will act as a server out in the field, clients will need a known IP address to contact. DHCP may still be used if the DHCP server is configured to recog- nize the EM1500, and (for example) always assign it the same IP address.

  • Page 46: Serial Tab (For Ser1 - Ser4)

    75 and 230400 in this field. The number should match the data transfer speed of the attached serial device. The EM1500 serial ports may all be configured for a wide range of bit rates, including non-standard speeds. The actual rates which are obtainable must be equal to the base clock divided by an integer between 6 and 256 inclusive.
  • Page 47 If you want 2 stop bits (only 1 stop bit is supported in the hardware), you may simulate it in software by choosing “Mark” for parity. This looks like an extra stop bit in the data stream. NOTE: Data bytes received with parity error are not transmitted to the peer. www.rabbit.com EM1500 User’s Manual...
  • Page 48 • (hardware) - CTS is an input to the serial port. When asserted it means that the attached serial device can accept more data from the EM1500. • XON/XOFF (software) - sent by the device receiving data to stop or restart the data flow.
  • Page 49 Flow control Rx The EM1500 can buffer up to 1020 characters. After that the network throughput must be high enough to avoid dropped data. The flow control options to control reception on SER1 are: • None - No flow control on the receive line.
  • Page 50 If the relay is already “on” (closed) then an action of “Momentary on” will have the effect of leaving the relay on for the specified momentary interval, then turning it off. www.rabbit.com EM1500 Configuration...

  • Page 51: Serial Tab For Rs485

    If “Rx Idle” was chosen for transmitter enable control, this parameter specifies the time interval which Rx must be idle before the unit can enable the transmitter. The relay configuration parameters are the same for the RS-485 port as they are for the other serial ports. www.rabbit.com EM1500 User’s Manual...

  • Page 52: Modem Tab

    This is an industry standard command set; however, most manufacturers have slight variations from the original standard. The EM1500 is not a normal telephone line modem, so many of the original AT commands are not relevant (such as whether Bell or CCITT signalling is used).
  • Page 53 The advantage of supporting an industry standard command set is that legacy serial devices that know how to talk to a modem can now talk to the EM1500 without know- ing the difference. The serial device becomes “network enabled” without significant work.
  • Page 54 Disconnect from remote host (“hang up”). Note that on standard modems, this controls the hook switch. There is no concept of a hook switch on the EM1500, so this always disconnects the current connection if one is established: H0 and H1 have the same effect.
  • Page 55 SER1, SER2 and possibly SER3. The choices are: • Active - always asserted 1. This control may be overridden by AT commands or by RFC2217 control. www.rabbit.com EM1500 User’s Manual...
  • Page 56 5- or 9-wire port. Either of these configurations preclude the use of SER4 as a 3-wire port. Third, in a future release of the EM1500, an internal modem will be available that will use SER4 even when SER3 is configured as a 5- or 9-wire port. The configuration program refers to this future option on the Modem tab for SER3 and SER4;...
  • Page 57 SER4 is internal modem SER3 5-wire TTL SER4 is internal modem SER3 9-wire RS232, true 5-wire (DSR, DTR, DCD, RI are 0-3V, Tx, Rx, RTS, CTS are +/-5V) SER4 not available SER3 9-wire TTL SER4 not available www.rabbit.com EM1500 User’s Manual...

  • Page 58: Polling Tab

    N wires are at correct standard levels. 5.1.7 Polling Tab This is an advanced setting that is only visible when View | Advanced is checked. The same polling options are available on all 5 serial ports. www.rabbit.com EM1500 Configuration...
  • Page 59 Note that polling is inserted by the EM1500 at arbitrary points (from the point of view of the attached device or network peer). Thus, if you select the “Poll when connected” option, there may be undesirable interaction with the normal data stream.
  • Page 60 60 seconds). Note that this is a minimum time interval. The time might be longer than this for two reasons: • the EM1500 is busy doing other things • packetization is in use, and a packet has been partially received www.rabbit.com...
  • Page 61 The device may be in the process of sending previous data. This data is intercepted by the EM1500 while it is looking for the OK response. The data will be discarded, or may be passed through to the network peer.
  • Page 62 If the script has syntax errors, they may not be discovered until the script executes. Current syntax errors are unbalanced quotes and trailing unescaped backslash. If there is an error in the script, then polling will be turned off. www.rabbit.com EM1500 Configuration...

  • Page 63: Opening Tab

    Set to zero to make this entry unused. Port numbers less than 1024 are reserved; they are used for internal function- ality and standard services such as web server and telnet. Table 5.3 Default Port Numbers EM1500 Serial Port Responds to TCP Port # SER1 8888...
  • Page 64 When checked, outgoing connections use a local ephemeral TCP port number. Other- wise “Local TCP port” is used. Check this option if the EM1500 is acting as a client on this serial port. Use Nagle When checked, TCP connections buffer outgoing data using the Nagle algorithm.
  • Page 65 Char to open (decimal) If specific character causes open, this is the character. Specify a decimal number 0 thru 255. For example, “13” for carriage return or “10” for line feed. Available with all serial ports. www.rabbit.com EM1500 User’s Manual...

  • Page 66: Closing Tab

    Available with SER1 and SER3 configured as a 9-wire port. “Modem control, not close on DTR drop” is available on SER2. DCD dropped Close when DCD (RLSD) line is dropped. Available with SER1 or SER3 config- ured as a 9-wire port. www.rabbit.com EM1500 Configuration...
  • Page 67 Set this to at least a few thousand ms to prevent excessive network traffic in the case that something is misconfigured, e.g., the connection gets a close condition immedi- ately after opening. www.rabbit.com EM1500 User’s Manual...

  • Page 68: Protocol Tab

    When checked, try to negotiate Rabbit extensions to RFC2217 protocol. This is rec- ommended when connecting two EM1500s for use as a transparent serial bridge. If the peer does not understand the extensions, this option will not cause any problems. This is required if any packetizing options are specified. www.rabbit.com EM1500 Configuration...
  • Page 69 Minimum time that serial port transmitter is idle before sending new packet to serial port. This value is rounded up to a multiple of 1/2048 seconds (i.e., about 488 µs). Available when “Idle” is chosen as the packetizing option. www.rabbit.com EM1500 User’s Manual...

  • Page 70: Status/Debug Area

    The listbox at the top left of the display shows a list of the EM1500s that can be contacted (among other things). If you click on one of the EM1500 icons to highlight it, then the area below the listbox becomes a status display for that unit.
  • Page 71 When you click on the EM1500 icon to select it, the GUI sends a message over the network to the selected unit, telling it to send status updates on a regular basis, or when anything changes. After that, the EM1500 is responsible for sending messages to the GUI so that it can update the display in “real time.”...
  • Page 72 If you click on a button, a message will be sent to the EM1500 to change the state of the control. If it can change the control, the EM1500 responds with a confirmation message that updates the display. For exam- ple, if you click the “Relay”...
  • Page 73 The manual controls are: • M/C: this forces the EM1500 into or out of Hayes modem emulation mode. You should not do this if a connection is currently open, since it may confuse the device attached to the serial port.
  • Page 74 Hopefully, this situation will not last too long. When the first serial device eventually finishes process- ing its backlog, it will reassert its RTS. The EM1500 will not be stalled any more, so the Flow LED will go off. Now the serial port transmit buffer will start draining. The bar graph will diminish, but sometimes go up again if data is staged from the network buffer to the serial transmit buffer.

  • Page 75: Differences Between Configuration Methods

    1. A web browser requires you to know a valid IP address for the EM1500 before it can be contacted. The stand-alone program can make contact with an EM1500 on its same LAN prior to an IP address being assigned to the unit.
  • Page 76 EM1500 Configuration...

  • Page 77: Chapter 6 Em1500 Examples

    Now, whatever you type in one terminal emulator window travels out its COM port, through the serial port of the EM1500, out its Ethernet port to the Ethernet port of the other EM1500, out through that EM1500’s serial port, in through the second COM port and almost instantly is displayed in the other terminal emula- tor window.

  • Page 78: Example 2: Remote Data Acquisition

    6.2 Example 2: Remote Data Acquisition This example describes using an EM1500 to transfer data received on a serial line to a remote host, where the data is automatically entered into an Excel spreadsheet. This simulates gathering data from a serial device, such as a bar code reader, and sending it to a remote destination for processing.

  • Page 79: Hardware Connections

    Active Open: When any char received Since the EM1500 will act as a client, you don’t need to have a static IP address if you have a DHCP server available to the EM1500. In this case, you may check Use DHCP on the Network tab to have a dynamically assigned IP address.
  • Page 80 2 text fields. This is where you choose the application that will receive the data coming in from the EM1500. The application defaults to Notepad. You can use this if you want, or you can try a more sophisticated program such as Excel.

  • Page 81: Appendix A Em1500 Specifications

    • information • Jumper locations for changing default behavior • Battery life and replacement A.1 Mechanical Characteristics The following figure shows the mechanical dimensions for the EM1500. Figure A-1 Black Box Dimensions 1.718’’ (44 mm) 4.180’’ (106 mm) 3.558’’ (90 mm) www.rabbit.com...

  • Page 82: Base Plate

    Figure A-2 Base Plate Dimensions Side of Unit Chamfer .10 x .10, 4 places 4.28’’ 3.78’’ (108.8 mm) (96 mm) .187D, 4 places 6-32 clear, 4x 0.25’’ (6.4 mm) 4.10’’ 0.25’’ (104 mm) (6.4 mm) 4.60’’ (116.8 mm) www.rabbit.com EM1500 Specifications...

  • Page 83: Specification Table

    A.2 Specification Table Table A.1 lists the electrical, mechanical, and environmental specifications for theEM1500. Table A.1 EM1500 Specifications Parameter Specification Microprocessor Low-EMI Rabbit 3000 at 44.2 MHz Ethernet Port 10/100Base-T Backup Battery 3 V lithium coin-type, 950 mA·h, supports RTC and SRAM...

  • Page 84: Em1500 Emi / Emc Information

    300 MHz are generally well below background noise levels. A.3.1 CE Compliance The EM1500 has been tested and was found to be in conformity with the following applicable immunity and emission standards. EM1500s that are CE-compliant have a label with the CE mark on the front panel...
  • Page 85 The recommended way to connect an EM1500 to a building ground is to mount the unit on a metal panel that is already grounded. Use a wire with a size of at least 20AWG (0.5 mm ), preferably stranded, to establish a con- nection between one of the screws holding the back cover in place and the protective building ground.

  • Page 86: Em1500 Fcc Compliance

    Units that do not have a CE mark can be made FCC compliant. Place a ferrite on the ethernet cable as close as possible to the EM1500’s ethernet jack. Loop the cable so that it passes twice through the ferrite. The characteristic should have a maximum attenuation in the 100-350 MHz range, or universal wideband.

  • Page 87: Em1500 Jumpers

    A.4.1 How to Access the Jumpers To access the jumpers remove the 4 screws that are in each corner on the back panel of the EM1500. The PC board (or main board) and back panel are attached to one another and will slide forward away from the black box housing.

  • Page 88: How To Move The Jumpers

    A.4.2 How to Move the Jumpers Zero ohm surface-mount resistors are used for JP1; this requires soldering to change position. Standard pluggable jumpers are used for the remaining headers. The table below lists the configuration options. Table A.2 EM1500 Jumper Configurations Pins Factory Header...

  • Page 89: The Backup Battery

    2.93 V or is removed from the circuit board. The drain on the battery is less than 10 µA when there is no external power applied to the EM1500, and so the expected shelf life of the battery is more than 950 mA·h...
  • Page 90 EM1500 Specifications...

  • Page 91: Appendix B Serial And Tcp Protocols

    ERIAL AND ROTOCOLS To realize the full potential of the EM1500, it is necessary to have some knowledge of serial and TCP pro- tocols. This appendix discusses both topics. There is a detailed description of the difference between a straight-through serial cable and a null-modem serial cable.
  • Page 92 like Tx and Rx. RTS is an output for a DTE, and tells the DCE whether or not it is willing to accept data. CTS is an output for DCE, and tells the DTE whether it is able to accept data. Thus: In the null-modem cable, RTS and CTS are also swapped over: 5-Wire Straight-Through...
  • Page 93 (mis)designed into a piece of equipment. The EM1500 includes one DE9 M, known as SER1, one DE9 F, known as SER2, plus a non-standard con- nector for SER3 and SER4. SER3 and SER4 are RS232 ports, but they has some restrictions including being implemented on a 10-pin header rather than the familiar DE9.

  • Page 94: Electrical Signals

    +/-12 V. Only if “TTL levels” are explicitly mentioned, should the 0/5 V levels be assumed. The reason this subject is brought up here is that, on the EM1500, SER3 can be configured for either set of voltage levels.

  • Page 95: Flow Control

    The bit rate, sometimes loosely referred to as the “baud rate,” may be any value but is usually selected from a small range of discrete rates such as 600, 9600, or 57600 bits per second. The EM1500 supports all standard rates between 75 and 230400 bps, plus many non-standard rates.
  • Page 96 If the EM1500 sees CTS being dropped, it will stop sending until CTS is asserted again. The EM1500 does not react instantly, since it only checks the CTS line at 488 µs intervals. Thus, at the highest supported speed of 230.4 kbps, up to 14 characters will be sent after CTS is dropped. This is not usually a problem, since most devices capable of operating at this speed have at least a 16- byte leeway.
  • Page 97 • On the sending side of the EM1500 serial port, if the attached device sends an XOFF character the EM1500 immediately stops sending normal data (although it may send XON/XOFF characters). If it receives an XON, it immediately resumes sending data if it has any to send.
  • Page 98 This is far greater than the total serial+network buffering, 5,000 bytes, available in the EM1500 for each direction. Hence, incoming data from the serial device might have to be dropped by the EM1500 before the sender sees the XOFF character that is still in the network. Similarly, the EM1500 might have several thousand characters buffered to send to the device even after the device sends an XOFF to pause the flow.

  • Page 99: Packetization

    In practice, this means that packetization is only supported when you are using an EM1500 at each end of the network connection. You can, however, write host code to support the Rabbit extension of the RFC2217 protocol. Contact Rabbit technical support for details. The extension specifications are openly available at no cost.
  • Page 100 Since the packet must be sent in one continuous stream, the entire packet must be buffered in the EM1500 before it can start being sent. If only part of the packet had been received from the network, the EM1500 could not start sending it since there is no guarantee that the rest of the packet will be received from the network in a timely manner.
  • Page 101 2. If “String - cut” is selected, then the EM1500 inserts the terminating string and sends it out the serial port. This is necessary because the network peer cut out the terminating string before sending the EOP.
  • Page 102 Very often, this character is treated specially, e.g. as some sort of address byte, but the EM1500 just considers it to be part of the normal packet data. If using 7 bit data for characters, the so-called 9th bit is actually the 8th bit, but for simplicity we retain the term “9th bit”...
  • Page 103 For example, some protocols may require a 2-byte checksum to be appended after the final CRLF that terminates the packet data. In this case, the “Trailing chars” field should be set to “2” to ensure that the checksum gets transmitted along with the packet. www.rabbit.com EM1500 User’s Manual...
  • Page 104 www.rabbit.com Serial and TCP Protocols...

  • Page 105: Appendix C Glossary Of Terms

    DCD - Data Carrier Detect (aka., RLSD, Receive Line Signal Detect), an output that should be asserted before sending The EM1500 may be used as either a DTE device or a DCE device, depending on the serial port being used. SER2 is a DCE device.
  • Page 106 DCD - Data Carrier Detect (aka., RLSD, Receive Line Signal Detect), an input the DTE expects will be asserted before receiving The EM1500 may be used as either a DTE device or a DCE device, depending on the serial port being used. SER1 is a DTE device. SER3 may also function as DTE device.
  • Page 107 The one-shot device is used in the design of the EM1500 so that the reset line can be polled at certain intervals to determine the operating mode of the unit.
  • Page 108 RS-232 Full-duplex, electrically single-ended serial interface standard. The electrical and some mechanical and protocol characteristics of the connection are defined including handshaking lines and a communi- cations protocol. RS-485 Half-duplex, differential mode, single driver, multiple receivers serial interface standard. Request to Send, a hardware flow control signal driven by a DTE device to tell a DCE device when to start or stop.

  • Page 109: Appendix D Em1500 Faq

    What do I do if my EM1500 is behind a firewall? • Help! I assigned an invalid IP address to the EM1500 and I can no longer talk to it. What should I • I am restarting a telnet connection. Why is it now refusing a connection? Serial ports •...
  • Page 110 • Can I monitor the data that is sent/received by a serial port? • I want the EM1500 to send a prompt to the device on a regular basis, but without expecting any particular response. Stand-alone configuration program • Why is the status/debug area of the program window blank? •...
  • Page 111 Why are there 2 types of serial cables in the EM1500 Tool Kit? The EM1500 is a DTE on serial port 1 (SER1) and a DCE on serial port 2 (SER2). If you want to connect 2 DTE devices to the EM1500, the straight-through cable would be needed for SER2 and the null-modem cable would be needed for SER1.
  • Page 112 In that case, you will either have to be behind the same firewall, or work with your network adminstrator to punch a hole through it. Help! I assigned an invalid IP address to the EM1500 and I can no longer talk to it. What should I do? First, don’t panic.
  • Page 113 Check your serial port settings. Are they the same on both sides of the connection? The baud rate, character size, parity setting and number of stop bits set for the serial port of the EM1500 must match those set for the attached serial device.
  • Page 114 "man in the middle", forwarding data to the real application, but also saving it off in a file for later analysis. I want the EM1500 to send a prompt to the device on a regular basis, but without expecting any particular response.
  • Page 115 The EM1500 can only send updates to one display at a time. The status/debug area can also go blank if the EM1500 is rebooted. In this case, select another entry, then reselect the EM1500.
  • Page 116 • The IP address is already in use by another device. • The EM1500 is remote (i.e. not on the same LAN) but there is no "router" defined for it to be able to communicate back to the PC, or the router IP address was incorrect.
  • Page 117 • Somebody reset the unit to factory defaults (i.e. by physically resetting the unit) and turned on their own secure config. If somebody did this, then you will have to sort it out with them (or reset to factory defaults again). www.rabbit.com EM1500 User’s Manual...
  • Page 118 EM1500 FAQ...

  • Page 119: Index

    .......54–58, 60, 63 emissions standards ....81 power supply ......12 FCC compliance ......82 relay ....8, 23, 30, 38, 68, 79 reset button .........22 reset to defaults ......5 RI ......48, 52, 61, 89 hardware connections ....11 www.rabbit.com EM1500 User’s Manual...
  • Page 120 router .......... 35 RS-485 ......... 26–29 RTS ........ 44, 52, 88 secure configuration ....35 send/expect ......57–58 straight-through cable 8, 12, 87–89 technical support ......9 throughput ........2 transmit buffer ......96 User LED ........22 voltage ........81 www.rabbit.com...

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