Bently Nevada 3500/50 Discrete Internal Barrier I/O Module 136703-01
Description:
136703-01 is Bently Nevada 3500/50 Tachometer Module Discrete Internal Barrier I/O Module with Internal Terminations. 136703-01 is connected to the 3500/50 main card 133388-02 or 288062-02.
The internal barrier I/O modules add approximately 50 mm (2 in) to the depth of the rack to provide the 50 mm (2 in) physical separation between safe and hazardous area field wiring.  Hence, a standard rack with internal barrier modules will not fit into a 400 mm cabinet. 
Dimensions: 241.3 mm x 24.4 mm x 163.1 mm
Weight: 0.46 kg (1.01 lb)
Ordering Information：
3500/50M Tachometer Module
3500/50-AA-BB
A: I/O Module Type
01  I/O Module with Internal Terminations
02  I/O Module with External Terminations
04  I/O Module with Internal Barriers and Internal Terminations
B: Hazardous Area Approval Option
00  None
01  CSA/NRTL/C (Class 1, Division 2)
02  ATEX/IECEx/CSA (Class 1, Zone 2)
Spares:
288062-02  3500/50M Tachometer Module
133442-01  I/O Module with Internal Terminations
136703-01  Discrete Internal Barrier I/O Module with Internal Terminations
133434-01  I/O Module with External Terminations
133450-01  TMR I/O Module with External Terminations

FAQ：
What's the firmware of 3500/50?
Revision 5.30 or later, not compatible with any version of 3500/20.