Upgrading of subscriber connection

Claim 1

Subscriber connection arrangement in a telephone network node, to which several twin-wire subscriber lines lead and through which subscriber terminal equipment has access to the telephone network, the node comprising: several subscriber interface units of an analog subscriber connection (POTS) and several subscriber interface units of a digital subscriber connection (e.g. ISDN) of a first type, to each of which the end of the subscriber line is connected and which adapt the signal coming from the subscriber line to the telephone network and correspondingly adapt the signal from the telephone network to a signal for transmission on the subscriber line, several test switches, each of which is located between the end of the subscriber line and the subscriber interface unit, a test unit controlling the test switch to connect the end of the subscriber line either with the subscriber interface or with the test bus, through which the test unit performs measurements concerning the subscriber line, whereby the test switches and thus the subscriber lines are arranged in groups so that the test switches of the group may connect the subscriber lines to a common line leading to the test bus, the node further comprising: a switch matrix bus formed of several wire couples and to several wire couples ( 1 , . . . , 8 ) of which is connected the subscriber interface ( 27 ) of a digital subscriber connection of another type, which interface performs adapting between the telephone network and a signal of another type propagating on the subscriber line, and in each group (UNIT 1 , . . . UNIT N), is a controlled switch element (SE 1 ,SE 2 ; SE 12 ,SE 22 ; . . . SE 1 N,SE 2 N) located on a common line ( 41 , . . . 4 N) between the test switches (R 1 , . . . ,RNn) of the group, which switch element connects the common line to one predetermined wire couple of the switch matrix bus or to the test bus.