Preliminary Release
Alligator Communications Model 2788 Technical Manual REV2.3 Copyright © 2019
Page 18
5.0 User Configuration and Diagnostic Menu
The 2788 uses a simple command line interface for configuring and monitoring key parameters
and metrics. Access is via IP Telnet. The 2788 is set to a default IP address of 192.168.1.128 at
time of shipment. The access is either local, using the Ethernet RJ-45 connector or remote
through the radio system. The command line interface facilitates writing scripts for automated
configuration. Contact Alligator for GUI based software utilities that front-end the Telnet
commands to simplify network management of multiple 2788 radios further .
Should it ever be necessary, an internal push-button resets the IP address to the default of
192.168.1.128 and default Telnet port to 23. The push-button also resets the password,
encryption phrase, and takes the unit out of password mode. The remaining parameters are
unchanged. (See Fig. 3)
5.1 Transmitter Frequency
The transmitter frequency is set in MHz with up to 9 significant figures. The allowed frequency
range is from 757 to 788 MHz. The full format is:
tf=###.######<CR>
The decimal point is optional. Trailing zeros are optional.
Examples: 757<CR> 757.0<CR> 757.1<CR> 757.12<CR> 757123456<CR>
5.2 Receiver Frequency
The receiver frequency is set in MHz with up to 9 significant figures. The allowed frequency
range is from 757 to 788 MHz. The full format is:
rf=###.######<CR>
The decimal point is optional. Trailing zeros are optional.
Examples: 757<CR> 757.0<CR> 757.1<CR> 757.12<CR> 757123456<CR>
5.3 Frequency Calibration
The 2788 frequency reference is a precision TCXO (Temperature Compensated Crystal
Oscillator) that is factory tuned to 1 ppm accuracy. Should it ever be necessary to adjust the
compensation, the following command permits trimming the PLL multiplier that directly affects
the TX and RX frequencies in steps of 1 Hz:
fc=xxxx<CR>
Examples: 100<CR> -100<CR> 10<CR> -10<CR>
Normally calibration is performed by transmitting a CW carrier (dt=1) and monitoring the
output frequency on a calibrated frequency counter.
