Summary of Contents for Embedded RM232-433
- Page 1 RM-232-xxx Radio Modem User’s Guide N11391 Embedded Communications Systems Specialists in Embedded RF Data Communications, Monitoring and Control Systems...
- Page 2 Please include in all email correspondence your name, company, modem type, modem serial number and firmware version. All information supplied to Embedded Communications Systems will be treated in the strictest of confidence. User’s Guide Page i...
-
Page 3: Table Of Contents
Contents Chapter 1 Introduction .......................1-1 About this Manual ......................1-1 The RM-232-xxx Radio Modem ..................1-1 Features..........................1-2 Chapter 2 Installation and Operation ................2-1 Serial Interface........................2-1 Connecting for the First Time.....................2-1 Front Panel Indicator Lights ....................2-4 Mounting the Radio Modem....................2-4 Positioning the Radio Modem ....................2-5 Potential RF Interference ....................2-5 Operating Problems ......................2-6 Chapter 3 Configuration Commands ................3-1... - Page 4 Chapter 5 Connecting The Radio Modem.................5-1 Serial Pinouts........................5-1 Connecting to a PC......................5-2 Two Wire Simplex Interface ....................5-3 Three Wire Half Duplex Interface..................5-3 Connecting to other DTE and DCE Equipment..............5-4 Chapter 6 Specifications ....................6-1 Chapter 7 Product Version Information ................7-1 Version Information......................7-1 Firmware Version Numbering Scheme ................7-1 Chapter 8 Modification History..................8-1 Bug Fixes &...
-
Page 5: Chapter 1 Introduction
Chapter 1 Introduction About this Manual This manual has been written for the RM-232-xxx range of low cost short range modems license exempt radio modems. The Radio Modems currently covered by this manual include the following: RM-232-151 VHF Radio Modem – Centre frequency: 151.300MHz RM-232-173 VHF Radio Modem –... -
Page 6: Features
Point-to-Multipoint Configuration and Broadcast Multi-drop Configuration Point-to-Multipoint Radio Link RS232 RS232 RS232 Master Unit RS232 Point-to-Point Configuration Point-to-Point Radio Link RS232 RS232 Local Host Remote Host Features • Acknowledged Point-to-Point and Point-to-Multipoint RF networks. • Acknowledged MultiMaster mode • Broadcast Multidrop mode •... -
Page 7: Chapter 2 Installation And Operation
Chapter 2 Installation and Operation This chapter describes basic connection procedures and operation. It also covers the front panel indicator lights and physical mounting and positioning of the radio modem. Serial Interface The RM-232 radio modem interfaces to external DTE equipment using a 9 way D type female connector. - Page 8 power switch is in the OFF position. Open the battery compartment on the back of the radio modem, connect and insert the battery before replacing the battery cover. The diagram below shows the recommended placement and orientation of the PP3 battery. Alkaline 9V PP3 Battery...
- Page 9 Starting your computer Switch your computer on if it is not already running, and start your favorite communications application (such as Hyperteminal for Windows). The radio modems are factory set to a default serial baud rate of 9600 bps, 8 data bits, 1 stop bit, no parity and no flow control.
-
Page 10: Front Panel Indicator Lights
Sending Serial Data Assuming both radio modems are connected and operating correctly, you are now ready to send some data. Ensure the two radio modems are spaced with at least 5 or more metres between them. Entering keystrokes in the communications application on one computer should result in those characters appearing in the communications application on the remote computer. -
Page 11: Positioning The Radio Modem
Attach the two strips of Velcro to the rear of the Radio Modem as shown. Placement of the adhesive Velcro on the rear of the radio modem. Positioning the Radio Modem In order to achieve maximum operational reliability and range from your radio modems it is important to reduce the possible effects of RF interference on them. -
Page 12: Operating Problems
Direct mounting of the radio modems to the case of computers, printers and monitors is not advised due to potential RF interference. A word of caution: Computers, printers and other microprocessor based equipment are renown for being big generators of RF interference. Ensure the radio modem is situated as far away from these devices as is practically possible. -
Page 13: Chapter 3 Configuration Commands
Chapter 3 Configuration Commands This section describes the configuration and test commands supported by the radio modem. In most cases, once the configuration is set it will not need to be changed. Configuration is performed using a serial terminal, organiser, PDA or appropriate communication application. -
Page 14: Configuration Commands In Detail
Configuration Commands in Detail help Display basic help information This command is used to display brief help information. For detailed help information the manual should always be consulted! exit Exit configurator This command exits the radio modem configuration mode and returns it to the data transfer mode. - Page 15 baud DTE baud rate This command sets the host interface (DTE) baud rate. The changed baud rate will take effect after leaving the configurator using the exit command. Using a DTE baud rate, with no flow control, greater than the radio through-put, you should be aware of the 96 byte serial internal receive buffer of the radio modem.
- Page 16 Command format: unit [n] where: n = [0-15] The unit address that a modem pair must be set to in order for them to communicate. site Radio Modem site address This command sets the device site code. Each site code can effectively support up to 16 different unit addresses.
- Page 17 addr Updates local memory unit, site and hop values This command sets the RAM based values for the unit address, site code and optionally the hop count. The command is provided in order to support continual programmatic changing of the unit address, site code and hop count in an acknowledged point-to- multipoint system.
- Page 18 DTR Control This command interprets how the radio modem responds to the state of the DTR signal and changes to the DTR signal. If the host device (DTE) interface does not provide a DTR signal then this setting should always be set to off. When DTR control is set to on and the DTR signal is not active, the Radio Modem enters a power saving shutdown state.
- Page 19 dlytx Delay data packet transmissions This command is used to set the delay between the last serial character received by the radio modem and the next packet of data sent from the radio modem. Radio network traffic is reduced by delaying packet transmissions until there is either a timeout of this delay period or there is enough data in the serial receive queue to transmit a complete full length data packet.
- Page 20 cmdchr Configuration escape character and guard time (user defined) This command allows the user to specify the ASCII value used for an escape sequence, and the pause time either side of the escape sequence. The default escape character is the ‘+’ symbol (ASCII 43). The default guard time is 1 second.
- Page 21 remote Remote unit configuration This command is used to either enable or disable the unit for remote configuration access. Once enabled for remote configuration access, the radio modem can be configured remotely by another radio modem using this command. Command format: remote [s] where: s = Enable remote configuration access to this modem.
- Page 22 rptmode Repeater mode This command enables or disables repeater mode. Please refer to chapter 4 for a detailed overview of the radio modem in repeater mode. Note that the repeater mode takes precedence over mode setting of ptpmode. Command format: rptmode [s] where: s = The radio modem acts as a network repeater for the current site...
- Page 23 seropt DTE serial options This command enables the user to select from several serial protocol options. Command format: ping [s] where: s = Sets 8 data, no parity and 1 stop bit. Sets 8 data, no parity and 2 stop bits. Sets 8 data, odd parity and 1 stop bit.
-
Page 24: Chapter 4 Modem Operation Explained
Chapter 4 Modem Operation Explained This section describes in detail the operation of a number of the radio modem’s configurable features. Flow Control The buffers in the radio modem and its flow control function permit serial communications even if the speed differs between the computer (DTE) and the modem DCE or between the radio modems (modem ports). -
Page 25: Xon/Xoff Flow Control (Software)
The radio modem provides three kinds of serial port flow control: hardware (RTS/CTS), software (XON/XOFF) and none. XON/XOFF Flow Control (Software) This type of flow control is performed by sending XON and XOFF control codes in the data stream. The XOFF code makes a transmission halt request, while the XON code makes a transmission restart request. -
Page 26: Radio Modem Addressing Scheme
Radio Modem Addressing Scheme The RM-232 radio modem provides a two tier addressing scheme applied to each outgoing packet of data. Seven data bits are used by the radio modem for data packet addressing, these being divided into a 3 bit site code (8 possible sites) and a 4 bit unit address (16 possible unit pairs). -
Page 27: On-Air Data Speed
On-Air Data Speed In a network of multiple radio modem point-to-point links, where network usage is at moderate levels, a situation occurs which results in each pair competing for air-time to transmit its data. The RM-232-xx enables user selectable throughput rates for the radio interface ranging from 600bps to 14400 bps (2400 bps for RM-232-151/173), thus improving network access.. -
Page 28: Dtr Power Control
DTR Power Control The RM-232 radio modem has three states of operation in terms of power consumption. Maximum power consumption within the radio modem occurs during data transfer. A short period after the data transfer has ended the radio modem enters a standby state whereby power consumption is more than halved. - Page 29 A receiving modem, upon receipt of a connect request, will send a connect acknowledgement to complete the link establishment phase. Once the communications link has been set up, data can then be exchanged between the Radio Modems. After no activity between the Radio Modems for a short period, both modems send a disconnect request message.
-
Page 30: Acknowledged Point To Multipoint
number of attempts an ACK message is still not received the link connection is effectively terminated and the data packet is discarded. The default setting for the number of data packet retry attempts is usually adequate for most situations. However if the radio modems are being used in an RF noisy environment or an environment prone to short signal interruptions (trucks passing between the link, etc) thus resulting in lost data, then the number of packet retry attempts should be increased slightly. -
Page 31: Broadcast Multidrop
Broadcast Multidrop This mode of operation is determined by the configuration command keyword ptpmode being set to OFF. Broadcast multidrop mode provides a mechanism for building very large networks using the RM-232 radio modem combined with intelligent host controllers. In broadcast multidrop mode, the radio mode does not implement network layer functionality related to data packet routing, acknowledgement and retries. -
Page 32: Repeater Mode
Repeater Mode This mode of operation is determined by the configuration command keyword rptmode being set to ON or ALL. Repeater mode takes precedence over the setting of ptpmode. Note that the RM-232-151/173 only supports a maximum of 1 repeater hop. -
Page 33: Diagnosing Network Problems Using Ping Test
A receiving radio modem will only accept a data packet whose hop count is zero. It is therefore essential that the correct hop count be specified in the modem configuration for the number of expected repeater hops. With rptmode being set to ALL, the repeater will retransmit all packets regardless of the site address, provided the hop count for that packet is greater than or equal to 1. - Page 34 Using the Radar function, a site test can be performed by placing one Radio Modem in a fixed position, then walking around the site with the second radio modem. It is best that the mobile unit be connected to laptop or PDA on which the radar test is run. The results are then immediately accessible while you are wandering around the site.
-
Page 35: Chapter 5 Connecting The Radio Modem
Chapter 5 Connecting The Radio Modem This section details the radio modem serial pin connections and describes various examples of connecting the radio modem to real world devices. Serial Pinouts The RM-232 DTE interface is via a 9 way female D type connector fitted to the side of the radio modem. -
Page 36: Connecting To A Pc
Connecting to a PC To connect the radio modem to a personal computer use the 9 way modem cables supplied. If the computer has a 25 way connector then the use of a suitable 25 way to 9 way adapter should be used. Note the remaining RS232 signals are not connected internally in the RM-232 radio modem. -
Page 37: Two Wire Simplex Interface
Two Wire Simplex Interface The radio modem can be used in a very basic two wire simplex connection. In this example, with no wake-up signal provided by DTR the Radio Modem is required to be permanently powered up. This is achieved by setting DTR control to off in the Radio Modem configurator. -
Page 38: Connecting To Other Dte And Dce Equipment
Connecting to other DTE and DCE Equipment For DCE and DTE equipment that require DCD and DSR be connected for proper operation, the following interface can be used. Note that the supplied serial cable does not provide the connections shown in the following diagrams. DTE Host Radio Modem Receive Data... -
Page 39: Chapter 6 Specifications
Chapter 6 Specifications General Radio Approvals Australian Standards AS4268.2 European Standards EN 300 220-3 & EN 301 489-3 FCC Part 15.249 (RM-232-914) Enclosure ABS Plastic with integrated battery compartment Optional TS35 DIN rail mounting bracket Interface Connectors RS232 Interface 9 way female D style configured as a DCE RS232 Signals RXD, TXD, RTS, CTS, DTR, GND Power-down control... - Page 40 Current Drain at 9V Transmit/Receive Average 40mA TBD for RM-232-151P & RM-232-433P Standby 15mA 400uA In power down state (10mW versions) Radio Transceiver General Single channel SAW controlled FM transmitter Double conversion FM superhet receiver SAW front end filter with full screening Frequency RM-232-151 Single Channel VHF 151.300MHz Frequency RM-232-173...
-
Page 41: Chapter 7 Product Version Information
Chapter 7 Product Version Information Version Information The RM-232 products contain both a hardware and firmware version string. The firmware version information provides some information regarding compatibility with other firmware versions. The firmware version number is displayed both with the signon message and upon entering the command line configurator. -
Page 42: Chapter 8 Modification History
Chapter 8 Modification History Bug Fixes & Change History Version 1.06b Added “seropt” command to support serial data protocols of 8n1, 8n2, 8o1, 8e1. Broadcast mode now does not enter standby. This elminates operational problems associated with link establishment. Version 1.05a Added acknowledged point-to-multipoint operating mode. - Page 43 User’s Guide...
- Page 44 User’s Guide...