Spectra Precision ProMark 800 Reference Manual - Manual (Page 91)

79
RTK Implementation
CDMA:
• Based on CDMA technology (CDMA=Code Division
Multiple Access) spreading data out over the channel after
the channel is digitized. Multiple calls can then be
overlaid on top of one another across the entire channel,
with each assigned its own “sequence code” to keep the
signal distinct.
• No specific frequency band per country.
Activating a Data Link in CSD Mode (GSM Only)
In this mode, you will have to:
• Make sure the base and its modem or cell phone have
been set up properly, and are operating.
• For GSM, choose the frequency band (according to
country).
• Dial the phone number of the base.
If set accordingly, the following parameters will facilitate the
activation and deactivation of the data link:
• Auto-dial: The phone number will automatically be dialed
right after the rover modem has been initialized.
• Number of re-dials: In case of unsuccessful connection,
the rover will automatically re-dial the base phone number
until the data link is established. After “x” unsuccessful
re-dials, the modem will automatically switch to the idle
state.
• Time out: The rover modem will automatically hang up if
no data is received via the data link for the specified time.
(This parameter can also be set on the base to deactivate
its modem if no data is transmitted for the specified time.)
An alarm will go off in the following cases:
• No phone number dialed
• Invalid phone number
• Line engaged
• All re-dials failed.