Midland Sp-400 Transceiver Users Guide

SP-400 Series User’s Guide  
If a 2-tone or selective Call 1 or Call 2 has been assigned for the 
selected channel, it may be sent by pressing the PTT button then 
pressing the upper (Call 1) or lower (Call 2) function button. 
If your transceiver has been programmed to send an emergency 
call for the selected channel, it may be sent by pressing the 
lower then upper function buttons, and holding them pressed for 
at least two seconds. 
! Please consult your dealer or communications 
coordinator before...

 SP-400 Series User’s Guide 
customize the scan options for your particular situation, so the 
following paragraphs detail the available options. 
Busy channel scan 
If no priority channel has been programmed by your dealer or 
communications coordinator, all channels in your scan list will be 
checked for activity, with no preference given to any channel. If 
activity is detected on a channel the radio will stop on that 
channel. Depending on programming, the radio may resume 
scanning after a...

SP-400 Series User’s Guide  
Transmitting while in scan mode 
If PTT is pressed while the radio is in scan mode, your dealer or 
communications coordinator may have programmed one of the 
following options for the transmit channel: 
1. When PTT is pressed, the radio will generate an error beep 
because your dealer or communications coordinator has 
programmed the radio to not allow transmission while the 
radio is in scan mode. 
2. When PTT is pressed, the radio will switch to and transmit 
on the...

 SP-400 Series User’s Guide 
Advanced Operations 
Operating hands-free 
VOX (voice operated transmit) is a method that allows the 
transceiver to automatically begin transmitting when it detects 
sufficient audio from an optional headset microphone. Correct 
VOX operation generally requires specific headset microphone 
circuitry, and not all headsets that otherwise function correctly on 
the radio may work properly in VOX mode. 
 Please be aware that the PTT button on the transceiver 
is disabled when...

SP-400 Series User’s Guide  
Selecting VOX sensitivity 
When VOX is activated you may toggle between low and high 
VOX sensitivity by pressing the lower, then upper function 
buttons, and releasing both within two seconds. A high beep will 
sound when high sensitivity is selected and a low beep will 
sound when low sensitivity is selected. 
Using the scrambler 
The SP-410 / SP-420 / SP-430 / SP-440 transceivers feature a 
built-in voice inversion scrambler. The scrambler function must 
have been enabled...

 SP-400 Series User’s Guide 
 If only two channels remain in the scan list, it is not 
possible to delete either of them. 
 When the radio is turned off (not when scan is turned off) 
the programmed default scan list will be restored. 
 Scan list edit is only available when scan is not turned 
on. 
To add or remove the current channel from the scan list press 
and hold the lower function button for more than two seconds. A 
low beep will indicate the channel was removed from the scan 
list. A high...

SP-400 Series User’s Guide  
 To avoid damaging the power cable of the battery 
charger, do not put anything on it or place it where it 
will be walked on.  
 Do not use the charger if it received a strong shock, 
has been dropped or it appears damaged. Contact 
your dealer or communications coordinator for a 
replacement charger.  
 Never try to disassemble or service the charger 
yourself. Always contact your local dealer or 
communications coordinator for assistance. 
 To reduce the risk of...

 SP-400 Series User’s Guide 
The battery pack must be charged prior to use. To charge the 
battery pack you should set up the charger and insert the radio 
(or battery) as follows: 
1. Plug the AC adapter into a grounded AC power outlet which 
supplies the specified input voltage for the AC adapter. 
2. Connect the DC plug on the AC adapter to the mating socket 
on the back of the charging cradle. 
3. Make sure the radio is switched off. 
4. Insert the radio into the cradle with the front of the radio...

SP-400 Series User’s Guide  
Memory effect 
The NiMH (Nickel Metal Hydride) battery pack is made with a 
more advanced technology than a NiCd (Nickel Cadmium) 
battery. For this reason it is virtually free of what is called 
“memory effect”, which affects NiCd batteries. Memory effect 
causes a reduction in the battery’s capacity. However memory 
effect may occur if you regularly charge the battery when you 
haven’t discharged it at least at 50-70%. Memory effect can be 
easily avoided by following...

 SP-400 Series User’s Guide 
5. Fully charge the battery and check the battery capacity. If 
you believe some memory effect still exists go back to step 
1. 
 If the battery capacity does not improve after performing 
steps 1-5 three times, your battery pack is faulty or has 
reached the end of it’s life. 
Cleaning your radio 
Wipe the radio with a clean cloth to remove dust. If it is very dirty, 
you can use a damp cloth. 
Clean the battery contacts with a clean, lint-free cloth to remove 
dirt,...