20 Description of the Radio Interfaces TM8000 3DK Hardware Developer’s Kit Application ManualSeptember 2003 © Tait Electronics Ltd2.3 Auxiliary ConnectorThe auxiliary connector is the standard interface for external devices that aretypically connected to a radio. The auxiliary connector is a 15-way standard-density D-range socket. The auxiliary connector provides a serial port, threeprogrammable input lines, four programmable digital I/O lines and audioI/O.Note The space for a mating plug is limited to 41mm in width and18mm in height. Although most plugs will fit this space, it is rec-ommended to test the plug to be used before manufacturing acable. The internal options kit (described on page 89) includes asuitable plug (Tait IPN 240-00020-55).If the auxiliary cable is longer than 1 metre it is recommended to shield thecable and connector backshell. Figure 2.5 shows the recommendedshielding arrangement. The earth braid wire (bare copper) and aluminiumfoil should only be earthed at the radio end of the cable.The I/O lines can be programmed for a variety of functions, logic levels andin some cases direction (refer to “Programmable I/O Lines” on page 39 ).Audio lines can also be programmed to tap into or out of different points inthe audio processing chain (refer to “Audio Tap In and Tap Out Lines” onpage 80).Figure 2.5 Recommended auxiliary cable and connector shieldingcable insulationaluminium foilearth braid wiresignal earth wireanalogue ground pinmetal backshellmetal D-range shroud incontact with backshellmetal cable clamp
