Inductive Modem Module Comparison to SIM and OEM UIM

The table below compares features of the IMM to the Surface Inductive Modem (SIM) and OEM Underwater Inductive Modem:

(1) The Underwater Inductive Modem is a component used by OEMs to integrate Sea-Bird's inductive modem technology with a third-party sensor.
(2) The SIM and UIM have a delay between adjacent bytes, resulting in only 100 bytes/sec transmission instead of 120 bytes/sec.


(Inductive Modem Module)

(Surface Inductive Modem)

(Underwater Inductive Modem)  (1)

Deployment History (as of 2014)

8 years

16+ years

14+ years

Maximum Data
Transmission Rate

1200 baud,
120 bytes/sec

1200 baud,
100 bytes/sec  (2)

1200 baud,
100 bytes/sec  (2)

Typical Power Consumption

1 mA at 12V

30 mA at 12V

15 mA at 12V

Physical Size

32 mm x 70 mm

100 mm x 150 mm


Additional Features

  • Includes wake-up tone detect capability
  • Binary data support is standard feature
  • Nonvolatile memory for configuration / data storage
  • Detailed device specification
  • Allows additional wake-up tone detection board
  • Available in direct cable connection (SIM-Direct) and coupled (SIM-Coupled) versions
  • Limited future applications, will slow phase out of production
  • Limited future support
  • New applications not supported

Typical Applications

  • New buoy controller designs
  • OEM underwater instrumentation
  • New moored profiler designs
  • Miniature and low power applications
  • Distributed acoustic arrays
  • Legacy support for existing buoy controller designs
  • Legacy support for existing moored profilers