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 900-928 MHz, which is license-free 

2.  General 

 

2.0

 

Product Overview 

The pMDDL900 is a high-performance embedded wireless data transceiver.  
Operating in the 902 – 928 MHz ISM band, this frequency-hopping spread-
spectrum module is capable of providing reliable wireless data transfer 
between almost any type of equipment which uses an asynchronous serial 
interface.  The small-size and superior RF performance of this module make 
it ideal for many applications.  
 
While a pair of pMDDL900 modules can link two terminal devices (“point-
to-point” operation); multiple modules can be used together to create a 
network of various topologies, including “point-to-multipoint” and 
“repeater” operation. Multiple independent networks can operate 
concurrently, so it is possible for unrelated communications to take place in 
the same or a nearby area without sacrificing privacy or reliability. 
 

1.1  Features

 

Key features of the pMDDL900 include: 

  transmission within a public, license-exempt band of the radio 

spectrum

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 – this means that it can be used without access fees 

(such as those incurred by cellular airtime). 

 

a serial I/O data port  with handshaking and hardware flow 
control, allowing the pMDDL900 to interface directly to any 
equipment with an asynchronous serial interface. 

 

ease of installation and use – the pMDDL900 module uses a 
subset of standard AT style commands, very similar to those 
used by traditional telephone line modems. 

  all units in a system are physically identical, and can be 

configured as a master, repeater or slave using the AT 
command set. No hardware modifications are required 

  128 sets of user-selectable pseudo-random hopping patterns, 

intelligently designed to offer the possibility of separately 
operating multiple networks while providing security, 
reliability and high tolerance to interference. 

  encryption key with 65536 user-selectable values to maximize 

security and privacy of communications. 

 

32-bit of CRC error detection and auto re-transmit to provide 
accuracy and reliability of data. 

within North America; may need to be factory-configured differently for some countries.

 

Summary of Contents for pMDDL900

Page 1: ...Operating Manual pMDDL900 2X2 MIMO 900MHz OEM DDL Module 1W Revision 0 30 May 28 2019 Microhard www microhardcorp com...

Page 2: ...TIONAL WARRANTY Indemnification The Purchaser shall indemnify Microhard Systems Inc and its respective directors officers employees successors and assigns including any subsidiaries related corporatio...

Page 3: ...This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However th...

Page 4: ...45 cm this configuration can be co located with other antennas provided the sum of the MPE ratios for all the other simultaneous transmitting antennas incorporated in a host device is 1 0 0 567 0 433...

Page 5: ...iii Co Location Instructions iiv 2 GENERAL 1 2 0 PRODUCT OVERVIEW 1 2 1 OUTPUT POWER LEVEL 2 3 INSTALLATION 3 3 0 OVERVIEW 3 3 1 ESTIMATING THE GAIN MARGIN 3 3 2 ANTENNAS AND CABLING 5 3 2 1 Internal...

Page 6: ......

Page 7: ...a public license exempt band of the radio spectrum1 this means that it can be used without access fees such as those incurred by cellular airtime a serial I O data port with handshaking and hardware f...

Page 8: ...t is recommended that the lowest power necessary is used using excessive power contributes to unnecessary RF pollution Ideally you should test the communications performance between units starting fro...

Page 9: ...knowledge of the equipment being deployed The following four factors make up a system gain calculation 1 Transmitter power user selectable 2 Transmitter gain transmitting antenna gain minus cabling l...

Page 10: ...system gain and path loss Referring to the same example suppose the path loss is 100 dB the gain margin would be 40 dB which is more than adequate for reliable communication Path loss is a very compl...

Page 11: ...procedure for installing cabling and antennas for use with the pMDDL900 module 3 2 1 Internal Cabling The most common method for installing the module is to run a cable from the module s UFL connecto...

Page 12: ...rs The most effective protection against lightning is to install two lightning surge arrestors one at the antenna the other one at the interface with the equipment The surge arrestor grounding system...

Page 13: ...suitable Choose a Yagi with enough gain to ensure adequate gain margin When deploying the Yagi point the antenna towards the intended target ensuring the antenna elements are perpendicular to the grou...

Page 14: ...the maximum power setting of 30dBm Example 2 What is the maximum power the pMDDL900 can be set to comply with FCC and IC given the following equipment given a Yagi Ant Gain 12dBd and cable and connect...

Page 15: ...Antenna RPTNC Pigtail Patch Antennas MHS031440 8dBi 900 MHz Patch Antenna RPTNC Pigtail Omni Directional MHS031251 3dBd 900MHz Omni Directional Antenna Antenex RPTNC Pigtail MHS031461 3dBd 900 MHz Om...

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