... standard lengths up to 1 km, are ideal for testing single-mode fiber spans (up to 50 ... Telco and Broadband networks. Please call or email for information about other length OTDR fiber boxes and Network ... -mode, SMF-281000 m (3281 ft) x1, x2 — connectors for multimode cables, specify type (e.g. ST, SC)y1, ... y2 — connectors for single-mode cables, specify type (e.g. ST, SC, ...