Abacus 5000 supports the emulation of modem testing as a V90 Server. In a typical V90 test scenario, you need a V90 Server and a V90 Client. With Abacus working as V90 Server, you can perform a testing on a SUT (System Under Test) as a V90 Client. If you want to test a network’s capability in support V90 modem protocol, you need to provide a device capable of working as a V90 client. This can be a V90 modem available in electronic store. Furthermore, V90 server only works on a digital trunk (T1 or E1). Hence the interface to the SUT must be digital (T1 or E1). If users’ V90 modem is a 2- wire analog interface, it is required to go through a channel bank / multiplexer, or a SUT-Switch. Note also that the protocol is asymmetrical, with upstream working at maximum of 34 Kbps, and downstream 56 Kbps.