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Interfacing TNC's to Motorola Mobile Radios


Description:

There are two common families of Motorola mobiles that are used for packet. They are typically single unit (not remote head), with a 16 or 20 pin interface connector on the backside of the radio. There are older models such as the Maxtrac, Radius M100, M120 and similar. Newer models include CDM750's, CDM1250's and the entrie XPR series of mobiles.
16 Pin Connector:
RADIO
2
4
6
8
10
12
14
16
1
3
5
7
9
11
13
15

1 External Speaker (-)
2 External Microphone Audio
3 Push To Talk
4 Spare
5 Flat Transmit Audio
6 Spare
7 Ground
8 COR (Active Low)
9 Spare
10 Ignition Control
11 Receive Audio
12 Spare
13 Switched A+ Sense
14 Hook Switch
15 Internal Speaker (+)
16 External Speaker (+)

20 Pin Connector:
RADIO
20
2
4
6
8
10
12
14
16
18
19
1
3
5
7
9
11
13
15
17

1 External Speaker (-)
2 External Microphone Audio
3 Digital Input #1
4 Digital Output #2 (External Alarm)
5 Flat Transmit Audio
6 Digital Input #3 (UART_RX)
7 Ground
8 Digital In/Out #4 (UART_TX)
9 Digital In #5 (Emergency)
10 Digital In #6 (Ignition)
11 Flat/Filtered Receive Audio
12 Digital In/Out #7
13 Switch B+
14 Digital In/Out #8
15 RSSI
16 External Speaker (+)
17 BUS+
18 Boot Control
19 No Connection
20 No Connection

26 Pin Connector:
RADIO
2
4
6
8
10
12
14
16
18
20
22
24
26
1
3
5
7
9
11
13
15
17
19
21
23
25

1 USB Data +
2 USB Data -
3 VBUS
4 USB/MAP_ID/Ground
5 MAP_ID_2
6 MAP_ID_1
7 SW B+
8 Power Ground
9 External Speaker (-)
10 External Speaker (+)
11 External Transmit Audio
12 Audio Ground
13 AUX Audio Out #1 / RXD
14 Receive Audio
15 AUX Audio Out #2 / TXD
16 Ground
17 Push To Talk/GP5_1
18 Ground
19 Monitor/GP5_2
20 GP5_6
21 Channel Activity/GP5_3
22 GP5_7
23 Emergency Switch
24 GP5_8
25 Ignition Sense
26 VIP_1/External Alarm