Juniper ERX-O3O12P-MOD

4-port OC3/STM1 or 1-port OC12/STM4 POS Line Module: supports (4) OC3/STM1 POS or (1) OC12/STM4 POS interface(s) with 128MB of memory. Requires either an OC3/STM1 IOA or OC12/STM4 IOA. Supports 1:1, 2:1, 3:1, 4:1, and 5:1 line module redundancy.