System for the remote testing of a modem for a speed of transmission different from the speed of reception.

摘要

The invention relates to a system for the remote testing of a modem, particularly for a view data terminal, which modem has a 75-baud part for transmitting orders to the view data bank and a 1200-baud part for passing on view data messages from the bank to the view data terminal. In the case of a disturbance it can be determined from a central station whether the disturbance originates from the view data terminal or from the modem. With both bit rates the modem is tested under operating conditions, both parts being looped and use being made of self-synchronizing scramblers with the aid of which a pseudo-random bit pattern occurs on both parts.