Bently Nevada 3500/20-01-01-00 135031-01 RIM I/O Module with Modem Interface
Description：
135031-01 is 3500/20 I/O Module with Modem Interface. 135031-01 is 1 full-height rear slot and installed behind 3500/20 125744-02 Standard Rack Interface Module. 
The Rack Interface Module (RIM) is the primary interface to the 3500 rack. It supports a proprietary protocol used to configure the rack and retrieve machinery information. The RIM must be located in slot 1 of the rack (next to the power supplies).
The RIM supports compatible Bently Nevada external communications processors such as TDXnet, TDIX, and DDIX. While the RIM provides certain functions common to the entire rack, the RIM is not part of the critical monitoring path and has no effect on the proper, normal operation of the overall monitoring system. One RIM is required per rack.
For Triple Modular Redundant (TMR) applications, the 3500 System requires a TMR version of the RIM. In addition to all the standard RIM functions, the TMR RIM also performs "monitor channel comparison." The 3500 TMR configuration implements monitor voting using the setup specified in the monitor options. Using this method, the TMR RIM continually compares the outputs from three (3) redundant monitors. If the TMR RIM detects that the information from one of those monitors is no longer within a configured percentof the information of the other two monitors, it will flag that the monitor is in error and place an event in the System Event List.
The Rack Interface Module uses two I/O module types, the Rack Interface I/O Module and the Data Manager I/O Module. These I/O modules let you connect a 3500 host computer and Communication Processors (TDIX or DDIX) to a 3500 rack and let you daisy chain racks together.
This section describes how to use the connectors on the I/O modules, lists what cables to use, and shows the pin outs of the cables.
Only one Rack Interface I/O Module can be installed at a time behind the Rack Interface Module (in a Rack Mount or a Panel Mount rack) or above the Rack Interface Module (in a Bulkhead rack). 
Also, one Data Manager I/O Module may be installed between the Power Input Modules and the Rack Interface I/O Module (in a Rack Mount or a Panel Mount rack) or above the Power Supplies between the Power Input Modules and the Rack Interface I/O Module (in a Bulkhead rack). 
Dimensions:241.3 mm x 24.4 mm x 99.1 mm
Ordering information:

There are I/O modules match different requirements within the following ordering numbers:
135031-01  RIM I/O Module with Modem Interface
125768-01  RIM I/O Module with RS232/RS422 Interface
125760-01  Data Manager I/O Module