X.21bis - continued
If any other apparatus, including cable or wiring, is to be connected between the apparatus
and the point of connection to any particular digital circuit then that apparatus shall conform
to the following:
(a) the overall transmission characteristics of all that other apparatus shall be such as to introduce no material
effect upon the electrical conditions presented to one another by the apparatus and the particular digital
circuit;
(b) all other apparatus shall comprise only:
(1) apparatus approved for the purpose of connection between the apparatus and a particular digital
circuit; and
(2) cable and wiring complying with a code of practice for the installation of apparatus covered by
BS6328 : Part 7 or such other requirements as may be applicable.
