Bias Meter I-97-A is for measuring bias in teletypewriter signals and is used in connection with adjustment of spring tension in Western Union 41-C type relays as used in Line Unit BE-77, a component of Telegraph Printer Sets EE-97 and EE-98.
References
- Bias Meter I-97-A War Dept. Aug.14, 1943
TM 11-2200 1943