Abstract: An auxiliary connection mechanism for allowing a Digital Switching System (DSS) to share an analog line with an analog device (via an auxiliary device port) is disclosed. The auxiliary connection mechanism includes a pair of relays for releasably connecting the auxiliary device port and the DSS to the analog line. When the analog line is idle, both the analog device and the DSS are connected to the line in order to receive incoming calls on the analog line. However, once one of the devices (either the analog device or the DSS) uses the line, the other device should not access the line. A busy line detect circuit is included to detect whether a device is using the line.

Abstract: A pin connection arrangement spanning a series of slots on a backplane 1 printed circuit board. The arrangement allows replaceable printed circuit board assemblies to be paired or mated while further allowing the printed circuit board assemblies to vary incrementally in width. The printed circuit board assemblies can be one slot wide 10a, 10b, two slots wide, 12a, 12b, three slots wide, 14a, 14b, on up to ‘n’ slots wide while being paired to a mate for sparing purposes. Backplane 1 provides a direct connection between paired printed circuit boards. The arrangement(s) allow expansion of printed circuit board area and volume while supporting paired applications that require only a single slot for a backplane connection per printed circuit board. Backplane 1 can be used for different width printed circuit board assemblies.