User`s manual
100-M0056X2B    10 of 28 
www.cobham.com/gms 
6.1.1  MDT-B Connectors 
There are three connectors located on the MDT-B unit as shown in Figure 2. They are for 
interfacing the RF, SDI/ASI, audio, video, power, RS-232 signals. 
6.1.1.1  RF Output 
The MDT-B uses a female SMA bulkhead connector for its ‘RF Output’ port. 
Note: Transmitters should not be powered on without a load. Doing so could 
cause the output PA to stop working. 
6.1.1.2  I/O 
The ‘I/O’ connector is a male, high-density DB-44. It is used to provide the interface for 
external power, audio, analog video and RS-232 signals. The MDT-B has a separate 
RS232 channel (labeled “Control” on the external breakout cable) for control and 
monitoring the unit. GMS MDLB Configurator software program (as explained in section 
6) makes use of the RS232 control lines. The RS-232 channel utilizes a 3-wire 
configuration. The pin out for the I/O connector is shown in Table 1. NOTE: A USB 
connector and an additional RS232 channel ( labeled “DATA”) are currently provided with 
the external breakout cable . The USB interface is an alternate method of interfacing to 
the PC if DB-9 connectors are not available. The “Data” RS232 channel is dedicated for 
low-rate data to be transmitted along with the audio and video. 
6.1.1.3  SDI/ASI Input (optional) 
A BNC connector is provided for Serial Digital or Asynchronous Digital data streams. 
Table 2 - I/O DB-44 Connector Pin Out 
Pin  Signal  Notes 
1  RS232 Data Tx 
2  RS232 Data Rx   
3  RS232 GND   
4  Not connected   
5  SDA  I^2 C bus 
6  SCL  I^2 C bus 
7  CVBS/Y 
Dual use input. 1. Composite video in; 2. 
Luminance in (when used with S or Component 
Video). Must be selected with GMS Control Software 
or through the front panel of the in-line camera 
mount box 
8  GND  GND for composite video 
9  C/Pr 
Dual use input. 1.Chroma video (when used with S-
video); 2. Pr (red component when used with 
Component Video). Must be selected with GMS 
Control Software or through the front panel of the in-
line camera mount box. 
10  GND  GND for chroma video/Pr component 
11  Pb  Blue component when used with Component Video. 
12  GND  GND for Pb component 
13  GND  GND 
14  11-15Vdc  Input power to unit 










