Click for homepage
USA
NSA
FILL
Crypto
Radio
  
DS-102 →
  
DS-101   EKMS 603
Common fill interface protocol

DS-101 is the current interface standard for electronic transfer devices, or fill units, developed and endorsed by the US National Security Agency. It superceedes the older DS-102 standard and is supported by nearly all modern radio sets and encryption devices, although most equipment is still backwards compatible with DS-102. DS-101 is supported by FILL devices like the AN/CYZ-10 and is described in the EKMS 603 standard. Unfortunately, this standard is not publicly available.

It is known however, that DS-101 is an asynchronous serial protocol, commonly implemented as an RS-485 interface, but RS-232 versions exist as well. In many cases, FILL devices support the newer RS-485/RS-232 asynchronous interface, as well as the older synchronous interface. Unlike the DS-102 standard, which could only transfer cryptographic keys and frequency hopping data, DS-101 can also be used for updating cryptographic algorithms and for new software releases.


DS-101 fill units on this website
AN/CYZ-10 Data Transfer Device
DS-101 compatible devices on this website
Narrow-band Voice and Data Terminal KG-40A Replenishment
Connection
For connection between the FILL unit, and a radio or encryption device, most devices used a standard U-229 connector. In many cases, this connector is shared with the audio functions of a military radio, for example for the connection of a handset. This connector has 5 or 6 spring-loaded contacts, and is available in a male and female variant, as shown in the diagram below.


Although each variant has its own specific type number, they are often referred to as U-229/U, or simply U-229, after the female 5-pin cable part. The table below shows the pinout of this connector for the DS-102 standard. On encryption devices this connector is commonly used exclusively for the FILL function, but on radio sets it is often shared with the audio functions.

Pin DS-101 Description Note
A GND Ground (common wire)  
B RTS Request to Send  
C RX Data out of radio or crypto device  
D TX Fill data into radio or crypto device  
E CTS Clear to Send  
F - -  
Help wanted
At present, not much is known about DS-101, EKMS-603 and the underlying data structure. You can help us to expand this page by providing additional information about transfer devices that use DS-101, supported radios, supported encryption devices, and the underlying data structure.

 Contact us


Further information
Any links shown in red are currently unavailable. If you like the information on this website, why not make a donation?
Crypto Museum. Created: Sunday 11 February 2018. Last changed: Sunday, 11 February 2018 - 14:06 CET.
Click for homepage