Справочник Пользователя для DEI Headquarters Inc. DEI487

 
 
 
 

 
 
 
 
 

Wednesday, May 12, 2004 
 
TUV Product Services 
10040 Mesa Rim Road 
San Diego, CA  92121 
 
RE: FCC ID EZSDEI487 
 
 
Dear Sir or Madam, 
 
This letter is to address the following for the 487VPX transceivers:  
 

1.  Learn routine for replacement transmitters 
2.  System transmission frequency range 
3.  Data transmission duty cycle description 
4. Manuals 

 
 
 

1.  Refer to installation guide pages 35 to 38. 
 
 
2.  This transmitter is a single frequency device. It has a crystal controlled PLL which generates the 

RF carrier. The crystal based oscillator can maintain a center frequency of 433.92MHz within a 
+/-35KHz tolerance. The receiver operated by this transmitter is a single band receiver tuned to 
433.92MHz and only capable of receiving this frequency. 

 

3.  The 487VPX is a data transmission device. Its protocol consists of 12 preamble bits (400us each) 

and 66 data bits (400us or 800us each, they are random) for a total of 78 bits. So the calculation 
for the duty cycle becomes: 

 

(12 x 400us)+(66x800us)= 57.60ms within a 100ms period 

 

The worst case scenario calculation is assured by the fact that we used 800us for all 66 data bits 
as they can be either 400us or 800us. 
 

4.  There are no dedicated manuals for this device. The 487VPX transceiver is part of several car 

alarm and remote start systems. Included are the installation and owner’s guides for the system 
with the most features which is representative of other, less feature rich systems. The owner’s 
guide of all systems have a section covering the operation of the transceiver.  Please refer to 
pages 5 to 12 in the owner’s guide.