TD220MAX_manual_v11.doc
05-6906A01
Page 7 of 49
7/31/2014
3.2 USB
The radio provides a USB Port conforming to version 1.1 of the USB standard. This port is provided
for features such as logging STFP messages to text files on a memory stick. Consult GE MDS for
information on this feature. The pinout for this connector is given in the table below.
Pin
Signal Name
Description
1
5V
+5 VDC
2
USBD-
USB Data Minus
3
USBD+
USB Data Plus
4
GROUND
Ground
3.3 Power
The power connector is a screw-secured 2-pin connector.
Pin
Signal Name
Direction with respect to MDS Equipment
Description
1 (L)
PWR
Input
13.8 VDC input, 7
Amps maximum.
2 (R)
GROUND
Input
Power return.
The pin orientation as looking into the connector is shown below.
Consult the following table to determine how much current is required for receiving or transmitting
vs. input voltage and RF power output. Duty cycle is a function of how many time slots of the 8 per
second are used for transmission. The STFP protocol used by the communications manager to send
data into the radio for transmission over the air specifies what time slot to use for each, so if the
communications manager uses all 8 slots, the duty cycle is 100%. If four are used every second, the
duty cycle is 50%. If 7 are used every 3 seconds (24 slots), the duty cycle is 29% (roughly 30%).
Many other duty cycles are possible depending on the epoch size and number of transmissions
within each epoch. If the duty cycle exceeds 29%, the RF output power is limited to 2 Watts. All MPE
RF safety calculations are based on the highest ERP levels.
Voltage (V)
RF Power Out
(W)
Duty Cycle (%)
Current Required
(A)
Thermal
Dissipation (W)
12
0 (RX)
0
0.3
TBSL
12
2
100
TBSL
TBSL
12
10
30
TBSL
TBSL
12
25
30
TBSL
TBSL
13.8
0 (RX)
0
0.3
TBSL
13.8
2
100
1.2
14
13.8
10
30
3.2
14
13.8
25
30
5.5
15
3.4 Antenna Connector
The Antenna Connector is a type N female connector with 50-Ohm characteristic impedance.
L
R
