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Summary of Contents for Midland SD-250
- Page 1 SD-250 User Guide...
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Page 2: Table Of Contents
Rev. 0B Contents Introduction --- 2 Preparing for use Unpacking and inspection --- 3 Description of modem --- 4 Features --- 5 External Connections --- 6 Pin Outs --- 7 Operation Channel Selection --- 9 Transmit/Receive Operation --- 10 Serial Commands --- 10 Status Indicators --- 12 Programming --- 13 Installation... -
Page 3: Introduction
Rev. 0B Introduction The SD250 range is a 1 to 6 Watts RF data module at VHF and UHF frequencies. The SD250 is housed in a rugged cast-aluminum box sealed to IEC 529 (IP54) making it suitable for a wide range of mobile and fixed applications. All SD250 RF data module units meet the essential requirements of the relevant directives. -
Page 4: Preparing For Use
Rev. 0B Preparing for use Unpacking and inspection Unpack the modem and check that you have received the following items: • SD250 RF data module • User Guide (this document) If any of these items are missing, please contact your supplier. -
Page 5: Description Of Modem
Rev. 0B Description of modem The SD250 is a network free, point to point RF data module that offers great flexibility in varied applications where wireless data or voice communication is needed. It can be used as a transparent radio, with no internal modem fitted, to allow users to facilitate the use of their own modem and protocol. -
Page 6: Features
Rev. 0B Features • Compact and rugged die cast box • Resistant to dirt, dust and water ingress (IP54 rated) • Network free, point to point communication • 1 / 6 watt programmable output power • Synthesized operation with 16 channel capability •... -
Page 7: External Connections
Rev. 0B External Connections 1. HD 9-way d-type (data, control signals and power supply) 2. BNC antenna connector... -
Page 8: Pin Outs
RS-232 level (option) Link 409 not fitted and link412 fitted. +12V = Tx -12V = Rx Data unfiltered OUT Discriminator audio from the SD-250. This is Analog signal (RX disc) the unprocessed AF signal prior to tone 1KHz audio at 60% filtering and de-emphasis. - Page 9 Rev. 0B Program: Read Note: If the option modem board is installed, RS-232 level (option) a resistor link can select RS-232 signal +12V = Tx levels. See Modem manual -12V = Rx Program : READ used for outputting TTL level only for programming data from mode radio program Ground...
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Page 10: Operation
Rev. 0B Operation Channel Selection Channels are selected by the use of internal switches and can be set as shown below. The top 4 screws will need to be removed to gain access to the switches, care must be taken to avoid any damage which could invalidate the warranty. The channel can also be changed by a serial command inputted from the external control system. -
Page 11: Transmit/Receive Operation
Rev. 0B Transmit/Receive Operation The SD250 is put into transmit/receive either by using TTL levels, RS 232 levels or serial command, depending on the application and modem set up. When the radio is used with no internal modem, TTL levels (pin 3 on DB9) can be used. - Page 12 Rev. 0B Byte0 Start bit 1 8-Bits (Command) Stop bit Byte1 Start bit 2 8-Bits (Data) Stop bit Byte2 Start bit 3 8-Bits (Check Sum) Stop bit Available Command and Data format Command Data Check sum ( 3 8-Bits ) Mode 8-Bits) 8-Bits)
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Page 13: Status Indicators
Rev. 0B Status indicators The LED indicates the current status of the radio and if an external speaker is connected to pin 9 of the DB-9, audible tones can be heard under certain fault conditions. The details are shown below: STATUS DESCRIPTION LED COLOR... -
Page 14: Programming
Rev. 0B Programming The data modem is a pc programmable modem. The parameters available for programming include: • Frequency, channel spacing and sub-audible tones on a per channel basis • Standard radio settings such as power save mode, scan, tx lockout, tx timeout •... -
Page 15: Installation
Rev. 0B Installation Antennas It is important that any antennas are installed in a suitable location with an adequate ground plane. Ideally, multiple antennas should be separated by a minimum of a wavelength (at the lowest frequency), whilst still retaining a good ground plane for each antenna. -
Page 16: Cabling
Rev. 0B Cabling If possible, run RF cables separately from other cables and keep RF cables apart from one another to avoid interference / coupling. When fitting the modem into a fixed installation care must be taken in the routing of all cabling such that the insulation cannot become damaged. -
Page 17: Safety And General Information
Rev. 0B Safety and general information Important information on safe and efficient use of your Radio device Exposure to radio frequency energy Your modem is a high power radio transceiver. When it is on, it receives and also sends out radio frequency (RF) signals. To help minimize human exposure to RF electromagnetic energy, keep transmission time to 50% or less. - Page 18 Rev. 0B Vehicles with airbags Air bags inflate with great force. Do not place a radio in the area over an airbag or in the airbag deployment area, any radio may be propelled with great force and cause serious injury to the occupant of the vehicle. Potentially explosive atmospheres Turn off your modem prior to entering any area with a potentially explosive atmosphere, unless it is a radio type especially qualified for use in such areas.
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Page 19: Warranty And Repairs
In the event that your SD250 RF data module needs repair, return your radio to an authorized Midland Radio supplier. Do not disassemble, modify or repair the unit unless the work is carried out by a Midland Radio approved supplier. Incorrect assembly, modification or repair may cause irreparable damage to your unit and will invalidate any warranty. - Page 20 Information provided in this document is believed correct at time of printing but is subject to change without notice. Midland Radio will not accept liability for any loss, damage or costs howsoever caused as a result of the information provided.
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