almanach network WAN

circuit switching (connection-oriented)
message switching (connectionless, messages sent)
packet switching (connectionless, messages splitted in packets)

router, multiplexer, CDU/DSU (channel service unit / digital service unit)

PSTN (public service telephone network)
POTS (plain old telephone system)

modems

DDS / switched 56
DDS (digital data service) dedicated line 56KBit/s
switched 56 circuit switched 56KBit/s

ISDN (integrated services digital network)
BRI (basic rate interface) 2xB-channel (64KBit/s) + 1xD-channel (16KBit/s)
PRI (primary rate interface) 23xB-channel (64KBit/s) + 1xD-channel (16KBit/s)

T1-T4
T1 24 channels 1.544MBit/s
T2 96 channels 6.312MBit/s
T3 672 channels 44.736MBit/s
T4 4032 channels 274.176MBit/s
each channel 64KBit/s voice or data
DS1-DS4 (when fibre optic is used)

X.25
packet switching protocol (high overhead, 64KBit/s max.)

SONET (synchronous optical network)

OC-1 51.840MBit/s
OC-3 155MBit/s
OC-12 622 MBit/s
OC-24 1.2GBit/s
OC-48 2.4GBit/s
OC-96 4.8GBit/s
OC-192 10GBit/s (80 wave lenghts, 1TBit/s)
OC-768 (320 wave length, 10TBit/s)