Midland Radio SD225U1 Users manual

User Guide

Contents

Introduction 2
Preparing for use 2
Unpacking and inspection 3
Description of modem 3
External Connections 3
Pin Outs 4
Channel Selection 5
Operation
Transmit/Receive Operation
Serial Commands
Status Indicators
Programming 5
Installation 5
Antennas 5
Power sources 6
Cabling 7
Fixing 7
Safety and general information 10
Warranty and repairs 12
Care of the equipment 12
Disposal / Recycling 12

Introduction

The SD225 range is a 1 to 5 Watt PMR data modem at VHF and UHF frequencies

The SD225 is housed in a rugged cast-aluminium box sealed to IEC 529 (IP54) making it suitable for a wide range of mobile and fixed applications.

All SD225 modem units meet the essential requirements of the relevant directives. In order to maintain this compliance the installation and safety information must be
adhered to at all times.

• The SD225 modem must only be installed where unintentional contact cannot be made. The surface of the device may be hot to touch under certain transmit
conditions. The SD225 is not designed for permanent transmission. If prolonged transmission periods are used, the unit will become hot and will require an
additional heatsink to be fitted.

• 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.

• The recommended supply sources for use with the SD225 are a standard 12V / 2A dc supply, but is capable of operating in the range 9V - 18V.

Preparing for use

Unpacking and inspection

Unpack the modem and check that you have received the following items:

• SD225 modem

• User Guide (this document)

If any of these items are missing, please contact your supplier.

Description of modem

The SD225 is a network free, point to point data radio 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. The correct signal levels need to
be used with the use of separate control lines, see the pin out table below.

The SD225 can also be fitted with a Bell 202/V23 modem (1200 baud rate). The internal modem allows communication with a pc using RS 232 for the data and control
lines. For further details, please refer to the modem manual.

SD225 has standard radio features available which are associated with a private radio. This includes CTCSS and DCS, software controlled squelch, time out timer
options and busy channel lockout as listed below (not all available with option modem fitted). There is a microphone input and speaker output to allow speech to be
transmitted and received.

Features

• Compact and rugged die cast box

• Resistant to dirt, dust and water ingress (IP54 rated)

• Network free, point to point communication

• 1/5 watt programmable output power

• Synthesised operation with 16 channel capability

• SAT when used with Bell 202/V23 modem or speech

• Programmable 12.5 / 25kHz channel spacing

• External modem / Direct FM

• Internal modem options available: Bell 202/V23

• ‘Busy’ output (can be set active high or low)

• 9 – 18 volt supply input

• Busy Channel lockout

• Time out timer