Programming and Syntax Diagram Conventions Introduction to Programming
Agilent 8163A/B, 8164A/B & 8166A/B Mainframes, Fifth Edition 27
Channel numbers apply to modules that have two inputs/outputs, for 
example, the Agilent 81635A Dual Power Sensor. 
Modules with two channels, for example, the Agilent 81635A Dual Power 
Sensor, use the channel number to distinguish between these channels.
For example, if you want to query slot 1, channel 2 with the command, 
“:SENSe[n]:[CHANnel[m]]:POWer:WAVelength?” on page 109, you should 
send the command: 
• :sens1:chan2:pow:wav?
Laser Selection Numbers
The laser selection number, [l], identifies the upper or lower wavelength 
laser source for dual wavelength Laser Source modules and Return Loss 
modules with two internal laser sources. The lower wavelength source is 
denoted by 1. The upper wavelength source is denoted by 2.
The Agilent 8164A/B slot for a back-loadable tunable laser module is 
numbered zero.
NOTE
The channel number of single channel modules is always one.
NOTE
If you do not specify a slot or channel number, the lowest possible number 
is used as the default value. This means:
• Slot 1 for the Agilent 8163A/B  and Agilent 8166A/B mainframes.
• Slot 0 for the Agilent 8164A/B mainframe.
• Channel 1 for all channels.
NOTE