User Guide

PAMS
Technical Documentation
NME–3
Technical Information
Page 62
Issue 1 10/99
External Signals and Connections
The handset is connected via curly cord to the system cable and then to
the RU. The curly cord uses an 10 pol western plug which will be
connected to the system cable.
HS Module Connector
Table 49. Handset connector
Pin Line Symbol Minimum Typical /
Nominal
Maximum Unit / Notes
1 N.C. not connected / HS
side =GND
2 MBUS 0
2.0
9600
0.8
2.8
5
5
V / low voltage
V / high voltage
µs / risetime
µs / falltime
baud/ transmission
rate
3 +8V 7,2 8,0 8,8
100
V / supply voltage
mA / supply current
4 GND ground from RU
5 HSEARP 17,5 501 mV / earpiece + to
earpiece –
6 HSEARN 17,5 501 mV / earpiece – to
earpiece +
7 PWR_ON
3.6
0.7
3.8
V / low voltage
V / high voltage
8 HSMICP 87 790 mV / microphone +
to microphone –
9 HSMICN 87 790 mV / microphone –
to microphone +
10 N.C. not connected / HS
side =GND
Pins 1 and 10 are connected to ground in HS for EMC protection
purposes and not connected in RU/ SCM–5.
Functional Description
Power On Key
Power ON/OFF key is connected to the RU via a seperate line. If the DC
level,delivered from the RU, is switched to ground the CCONT in the RU
detect this as power up of the system and switches on RU and HS.
Keypad Switch Matrix
Keyboard is held in SIMPLEX style. Keys are arranged in 4*4 matrix
structure and activities will generate an interrupt. The 4 horizontal rows
are routed to an input port of the MCU and the 4 vertical columns are
routed to an output port of the MCU. After reception of the keyboard
interrupt the SW can determine exactly which key was pressed.