Troubleshooting guide
PAGE 28 of 36  VR GSM DOOR INTERCOM TECHNICAL MANUAL    VER2.0.0 
CHECKING THE BALANCE 
*Note: The balance can only be checked if the correct balance check string has previously been 
stored using the SDL code explained earlier in the manual. 
The intercom also has the facility to monitor the available credit and then text you to inform you 
when it has fell below £5.00, €5.00 or $5.00. It will then remind you with another text after every 5 
calls until the credit is either increased or it runs out. To use this feature, the following settings 
must first be made:- 
o  You must be using a Pay AS You GO SIM card from a provider that offers this service (Vodafone, O
2
) 
o  The correct balance check string must be stored using the SDL code. 
o  A mobile phone number in which to receive the balance low text must be stored in location 020 using the 
STN code. 
UNDERSTANDING THE SIGNAL STRENGTH 
When a request for signal strength message is sent to the intercom panel it will reply with a two 
digit signal strength code. The code will be between 0 – 31 or 99. Ideally the signal strength should 
be as close to 31 as possible. The lower the number, the weaker the signal. Signal strengths lower 
than 10 may cause operational problems such as loss of speech quality (and possibly missing 
DTMF tones) and network loss. A signal strength of 99 indicates it could not be detected. 
DIALLING INTO THE INTERCOM FROM ANOTHER TELEPHONE 
There are three possible outcomes to dialling into the GSM intercom depending on the 
telephone number you are dialling in from and the features setup during programming. The 
three possible outcomes are shown in the table below and are shown in order of priority 
(For example, if the number is programmed to automatically activate the relay, this will 
take priority over the following two options and if the telephone number is stored as a 
telephone number called from one of the push buttons, this will take priority over the last 
option. 
FUNCTION 
REQUIREMENT 
PRIORITY 
Dial in to open the door. 
After dialling the number, the relay will 
activate and the call will be dropped. 
The telephone number of the telephone 
dialling in must be stored in memory location 
100 - 250 
1st 
Dial in to activate a call (Live speech, 
activate relay/AUXO) 
After dialling the number, the call will 
be answered and two beeps will be 
heard. The speech will then be live. 
The telephone number of the telephone 
dialling in must be stored in memory location 
001 - 020 
2nd 
Dial in to enter programming mode. 
After dialling the number, the call will 
be answered and two beeps will be 
heard. You will then be required to 
enter the four digit code to gain access 
to the programming menu. 
If neither of the two requirements above are 
met. 
3rd 










