User Guide

Technical Documentation
NHD–4
System Overview
PAMS
Page 3–11
Original 11/97
Signaling tone (ST)
Signaling tone is a plain 10 kHz tone. ST is used for signaling the base station
when the mobile phone is “off hook”, conversation is ended “on hook”, hook flash,
and handoff acknowledgment. When the mobile is being called,and is ringing, but
has not been taken “off hook” a continuous ST is transmitted to the base station.
When the mobile is taken “off hook”, answered, the ST is no longer sent. To
hang–up the “end” key is pressed, the mobile then sends out a 1.8 second burst of
ST. If during a conversation a mobile user wants “additional” service a
number/command is loaded into the mobile call memory and the “send” key is
pressed, the mobile will transmit ST for 400 ms. The base station responds will a
data acknowledgment, the mobile then sends its “additional” service request. When
a hand–off between base stations becomes necessary the MTX generates a
hand–off order and sends it to the mobile. The mobile stores this information and
sends a 50 ms burst of ST to the base station then changes to the new base station
and traffic channel. When the MTX detects SAT on the new channel the old base
station channel is shut down.
Base Station & Cell Set–up
Ch
333
313
329
327
330
315
322
Info Rxd
A4D7
B9CE
–––––––
796F
–––––––
BC43
–––––––
Level
–100 dBm
–109 dBm
–120 dBm
–118 dBm
–120 dBm
–116 dBm
–120 dBm
AMPS_10
333
101 – 150
A4D7
X
313
1 – 50
B9CE
320
201 – 250
8FB2
315
151 – 200
BC43
327
51 – 100
796F
Control Ch #
Traffic Ch #’s
Base Station
ID
Figure 10. AMPS: BS & Cell Set–up
When a cellular phone is first turned on it will scan the control channels. The phone
will record several different items of information, the channel number, Base Station
ID, System ID (SID) and the signal level of each Base Station received. In the
example Base Station A4D7 on control channel 333 was the strongest signal at a
level of –100 dBm. The mobile phone will then lock on control channel 333. Once
this is done the mobile phone is said to be “In Service”
BS
TX Registration
Channel 333
1.
2. Data ESN/MIN
3.
4.
Data A4D7 ”Service”
Data ESN/MIN OK
Data A4D7
AMPS_11
Figure 11. AMPS TX/RX registration