Keysight 34921A-34925A User’s Guide 35
34922A Simplified Schematic 
This drawing shows two independent 35-channel 2-wire MUXes.
LH
ABus2
DMM
(SENS)
ABus3 ABus4
ABus1
DMM
(MEAS)
001
002
003
004
005
H
L
006
007
HL
H
015
016
017
018
019
L
020
021
022
023
024
025
026
H
L
027
028
029
030
031
032
033
H
L
034
035
008
009
010
011
012
H
L
013
014
036
037
038
039
040
041
042
H
L
043
044
045
046
047
048
049
H
L
H
L
050
051
052
053
054
055
056
057
058
059
060
061
062
063
H
L
064
065
066
067
068
069
070
H
L
911
924
914913
923
912
921 922
LH
LHLHLHLH
LHLH
HL
Bank 1
Bank 2
COM 1
COM 2
Analog Buses
NOTE: 
Bank Relays:  Armature latching
Analog Bus Relays:  Armature 
non-latching
NOTE:  The three-digit number 
assigned to each switch 
represents the channel number.