Transmission system of high speed signal in apparatus

The number of paths interconnecting transmitting/receiving sections and channel sections are decreased. Two repeating switching sections (REP3-O, REP3-E) are provided between a group of transmitting/receiving sections (TRX1-1 to TRX1-N) and a group of channel sections (CH2-10, CH2-1E to CH2-MO, CH2-ME). The transmitting/receiving sections (TRX) and the repeating switching sections (REP) are interconnected, the channel sections (CH) and the repeating switching sections (REP) are separated into group O and group E. Connection paths are provided for the respective groups. For example, 2 (N+M) connection paths are provided between the repeating switching section (REP3-0) and the channel sections (CH2-10 to CH2-MO). Furthermore, the channel sections (CH) are grouped into pairs of O/Es having the same suffix numbers and each juxtaposed. Interchannel transmission lines (4-1 to 4-M) for transmitting/receiving transmission signals between the channel section (CH) and the repeating switching sections (REP) are formed of back wiring.