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Ritron, Inc. 
505 West Carmel Drive  

  Carmel, IN 46032 

P.O. Box 1998  

  Carmel, IN 46082 

Ph: 317-846-1201  

  Fax: 317-846-4978 

Email:  

[email protected]

  

  web: www.ritron.com 

 

Publication No. 14670028 

 

RQX 1-Series, 6-Series and 7-Series Callbox 

Modification for Always On Operation 

 
Ritron 1, 6, and 7-Series callboxes can be programmed for always-on operation by disabling the Automatic 
Turn-Off option.  This can be accomplished using the RQX PC Programmer or through Field Programming.  
Once Automatic Turn-Off is disabled, the user simply turns on the RQX by pressing the front panel PTT button 
and it will remain on as long as power is applied.  If power to the callbox is lost, the user must press the front 
panel PTT to restart the radio.  For externally powered callboxes, battery backup is one method of keeping the 
radio on if the primary external power is lost.   

For users that do not want to rely on battery backup, and do not want to “restart” the callbox after a 
power loss, the following modifications can be made to automatically restart the radio after a power 
loss.  

 

Important considerations before applying this modification: 

 

The Automatic Turn-Off option must be disabled. 

 

When Automatic Turn-Off is disabled the unit will consume the largest amount of current, but is always 
ready to instantly receive messages. This mode should only be considered if an external source of +12 
VDC is available. 

 

The callbox receiver will always be on.  All radio communication on the programmed frequency and tone 
will be heard over the RQX callbox. 

 
The callbox can be modified per the following instructions to automatically restart the radio any time power is 
applied and/or restored.   

1.  Carefully remove the PCB assembly per the instructions in the RQX Maintenance Manual (RQX-MRM-e). 

2.  Replace Q502 with an MMBD2835 (Ritron PN# 48A100A3) common anode, dual diode. 

3.  Add CR514 as an MMBD7000 (Ritron PN# 48A1005C) series dual diode. 

4.  Reassembly the unit per the RQX Maintenance Manual (RQX-MRM-e). 
 
 

 

CR514 (RTN# 48A1005C) 

Q502 (RTN# 48A100A3)

Detail of CR514 

location 

Detail of Q502 

location 

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