Motorola Gm1200e 68p64115b12 Manual

							Non Prescribed Data (NPD) Calls
NPD Application NotesB-1
1.0Non Prescribed Data (NPD) Calls
Non Prescribed Data calls utilising external Data Terminal Equipment (DTE) can be made using the 
GM1200E Databox radio as the carrier.
Call protocol is by a combination of control line handshakes, the complexity of which depends on the 
intelligence of the DTE.
2.0Calls with DTE connected to External Data Connector
(Radio Accessory Connector)
2.1DTE Initiated Call (Outgoing Calls)
n n nCall set-up is initiated on ‘Call 1’ which should be programmed with an address including the 
‘Non Prescribed Data’ (NPD) call modifier (*31*).
n n nWhen the traffic channel data path is set up, the radio will enable the audio input and output 
lines (with the microphone and loudspeaker lines disabled) and then signal that the DTE is 
Clear to Send (CTS).
n n nThe DTE will send and receive audio signals using the PTT line as direction control.
n n nCall clear can be from either DTE or radio.
DTE will remove the signal from ‘Call 1’ or signal on ‘Call Clear’.
Radio will remove the CTS line signal.
2.2Calls Initiated by another Radio Unit (Incoming Calls)
n n nIncoming calls will be indicated by a signal on the CTS.
n n nThe call will be “answered” by the DTE signalling on ‘Call 1’.
n n nThe call will continue and clear as described above in section 2.1
3.0Calls with DTE connected to Internal Data Connector
(Radio Option Connector)
3.1DTE Initiated Call (Outgoing Calls)
It is possible for the radio to call up to 3 different destinations (addresses) by using a combination of 
Call 1 and Call 2 lines to signal one of three possibilities (Call N).
n n nCall set-up is initiated on ‘Call N’  which should be programmed with an address including the 
‘Non Prescribed Data’ (NPD) call modifier (*31*).
n n nWhen the traffic channel data path is set up, the radio will enable the audio input and output 
lines (with the microphone and loudspeaker lines disabled) and then signal that the DTE is 
Clear to Send (CTS).
n n nThe DTE will send and receive audio signals using the PTT line as direction control.
n n nCall clear can be from either DTE or radio.
DTE will remove the signal from ‘Call N’ or signal on ‘Call Clear’.
Radio will remove the CTS line signal. 
						

							Other Calls
B-2NPD Application Notes
3.2Calls Initiated by another Radio Unit (Incoming Calls)
n n nIncoming calls will be indicated by a signal on the CTS.
n n nThe call will be “answered” by the DTE signalling on ‘Call 3’ (i.e.Call 1 and Call 2 lines both 
enabled).
n n nThe call will continue and clear as described above in section 3.1
4.0Other Calls
4.1Voice Calls
It is possible to set up voice calls internally or externally using the procedures described above by 
omitting the NPD call modifier from the called address. In this case the audio paths will be set up to 
use the external microphone and loudspeaker with the volume pre-set. It is not possible to adjust the 
volume from inside the radio.
4.2Status Calls
It is possible to signal status calls internally or externally.
n n nStatus is sent by signalling on ‘Call N’ to a pre-set address using the Status call modifier.
n n nThe radio will send the pre-set status call to the pre-programmed address.
n n nCall “success” will be signalled with a pulse on the CTS line.
4.3Mixed Calls
Due to the ambiguity necessarily introduced by the very simple handshaking techniques employed, 
users should only consider mixing Data/Voice/Status calls if they are confident that their DTE is 
capable of correctly interpreting the handshakes under all conditions for all incoming and outgoing 
call types likely to be encountered.