Abstract: An arbitration device for enabling a common resource to be shared by a plurality of processors, all connected by a common bus and each processor having a certain access priority. When more than one processor requests access to the resource, the highest priority processor request signal is latched and access is granted while the other requesting processor's latches remain set (access not granted). If two processors request access while the resource is busy, then only the latch of the processor having the highest priority of the two will be reset when the bus becomes available, and that processor will gain access.

Abstract: A DTE can control the modems attached thereto by transmitting command messages over the data path and analyzing report messages supplied by the modems in return. Each command message is identified by a specific header. A command message intended for a remote modem (34) is intercepted by the local modem (30) and reformatted so as to obtain a supervisory message that is then transmitted at the rate of one bit per baud. A command message intended for a remote multichannel modem (48) is transmitted either by a supervisory message or in the data mode of operation.

Abstract: Memory 60 contains a decision table which is a replica of the particular N-bit pattern to be detected. When a bit is received over line 12, a table lookup operation is performed to determine whether the entry at the address indicated by address counter 34 contains a bit that matches the received bit. If so, the content of the address counter is incremented by one and the device waits for another bit to be received over line 12. If the bit in the entry does not match the received bit, then, if the address indicated by the counter is zero, the count of the counter is maintained at zero and the device waits for another bit to be received; or, if the address is different from zero, the counter is reset to zero and the bit present on line 12 is again presented to the table in order, this time, to be compared with the bit in the entry at address zero. The pattern is detected when the address contained in the counter is equal to N and when the last bit in the pattern matches the bit with which it is compared.

Abstract: A method of testing a communication network that comprises a first and a second multiport modem communicating with each other through a transmission channel, each of said modems being provided with a number of input/output interfaces and each of the interfaces on either modem being associated with a corresponding interface on the other modem. In accordance with the method of the present invention, a test request is applied to one of the interfaces on the first multiport modem, which responds thereto by generating a test configuration code identifying that interface. This modem is then caused to assume a so-called test configuration, in which only that interface to which the test request was applied is active, and a test command comprising an indication of the test to be performed and a link level identifier is applied to that interface. If the identifier designates the link level to which the first modem belongs, this modem will control the test specified in the test command.