Command
Show Controller
Use
This command displays very detailed controller and interface information. Most of the time, you will only use this command to see if a serial link is a DCE or a DTE.
Syntax
Router#show controller <interface>
Example
In this example, we use show controller s1/1 | in DCE|DTE to see if the serial cable is DCE or DTE.
R1(config)#do sh controller s1/1 | in DCE|DTE cable type : V.11 (X.21) DCE cable, received clockrate 2015232
Here is the full show controller output
R1(config)#do show controller Interface FastEthernet0/0 Hardware is AMD Am79c971 ADDR: 644131C8, FASTSEND: 60037CDC, MCI_INDEX: 0 DIST ROUTE ENABLED: 0 Route Cache Flag: 11 LADRF=0x0020 0x0100 0x0008 0x0000 CSR0 =0x00000072, CSR3 =0x00001044, CSR4 =0x00004915, CSR15 =0x00000180 CSR80 =0x00001900, CSR114=0x00000000, CRDA =0x00000000, CXDA =0x00000000 BCR9 =0x00000001 CSR5 =0x00000001, CSR7 =0x00008000, CSR100=0x0000F000, CSR125=0x00005C00 BCR2 =0x00000000, BCR9 =0x00000001, BCR18 =0x00001960, BCR22 =0x00000000 BCR25 =0x000000FF, BCR26 =0x00000080, BCR27 =0x00000010, BCR32 =0x00000080 HW filtering information: Promiscuous Mode Disabled, PHY Addr Enabled, Broadcast Addr Enabled PHY Addr=CC01.1A80.0000, Multicast Filter=0x0020 0x0100 0x0008 0x0000 amdp2_instance=0x64414288, registers=0x3C000000, ib=0x7B237A0 rx ring entries=64, tx ring entries=128 rxring=0x7B23800, rxr shadow=0x64414840, rx_head=43, rx_tail=0 txring=0x7B23C40, txr shadow=0x64414974, tx_head=61, tx_tail=61, tx_count=0 Software MAC address filter(hash:length/addr/mask/hits): 0x54: 0 0100.5e00.000a 0000.0000.0000 0 0x57: 0 0100.5e00.0009 0000.0000.0000 0 0xC0: 0 0100.0ccc.cccc 0000.0000.0000 0 spurious_idon=0, filtered_pak=0, throttled=0, enabled=0, disabled=0 rx_framing_err=0, rx_overflow_err=0, rx_buffer_err=0 rx_bpe_err=0, rx_soft_overflow_err=0, rx_no_enp=0, rx_discard=0 tx_one_col_err=0, tx_more_col_err=0, tx_no_enp=0, tx_deferred_err=0 tx_underrun_err=0, tx_late_collision_err=0, tx_loss_carrier_err=0 tx_exc_collision_err=0, tx_buff_err=0, fatal_tx_err=0 hsrp_conf=0, need_af_check=0 tx_limited=0(64) PHY registers: Register 0x00: 1000 782D 0013 78E2 01E1 C9E1 000F 2001 Register 0x08: 0000 FFFF FFFF FFFF FFFF FFFF FFFF FFFF Register 0x10: 0104 4780 0000 0000 0000 0000 0000 Register 0x18: 0000 0000 00C8 0000 FFFF M4T: show controller: PAS unit 0, subunit 0, f/w version 1-45, rev ID 0x2800001, version 1 idb = 0x64418B4C, ds = 0x64419C0C, ssb=0x64419FC8 Clock mux=0x0, ucmd_ctrl=0x1C, port_status=0x7B Serial config=0x8, line config=0x200 maxdgram=1608, bufpool=78Kb, 120 particles DCD=up DSR=up DTR=up RTS=up CTS=up line state: up cable type : V.11 (X.21) DCE cable, received clockrate 2015232 base0 registers=0x3C800000, base1 registers=0x3C802000 mxt_ds=0x644A07A4, rx ring entries=78, tx ring entries=128 rxring=0x7B724C0, rxr shadow=0x64420624, rx_head=28 txring=0x7B72780, txr shadow=0x64420A00, tx_head=67, tx_tail=67, tx_count=0 throttled=0, enabled=0 halted=0, last halt reason=0 Microcode fatal errors=0 rx_no_eop_err=0, rx_no_stp_err=0, rx_no_eop_stp_err=0 rx_no_buf=0, rx_soft_overrun_err=0, dump_err= 0, bogus=0, mxt_flags=0x0 tx_underrun_err=0, tx_soft_underrun_err=0, tx_limited=1(2) tx_fullring=0, tx_started=1092, mxt_flush_count=0 rx_int_count=808, tx_int_count=1093 M4T: show controller: PAS unit 1, subunit 1, f/w version 1-45, rev ID 0x2800001, version 1 idb = 0x64424434, ds = 0x644254F4, ssb=0x644258B0 Clock mux=0x0, ucmd_ctrl=0x0, port_status=0x7B Serial config=0x8, line config=0x200 maxdgram=1608, bufpool=78Kb, 120 particles DCD=up DSR=up DTR=up RTS=up CTS=up line state: down cable type : V.11 (X.21) DCE cable, received clockrate 2015232 base0 registers=0x3C800000, base1 registers=0x3C802000 mxt_ds=0x644A07A4, rx ring entries=78, tx ring entries=128 rxring=0x7B84900, rxr shadow=0x6442BF0C, rx_head=0 txring=0x7B84BC0, txr shadow=0x6442C2E8, tx_head=1, tx_tail=1, tx_count=0 throttled=0, enabled=0 halted=0, last halt reason=0 Microcode fatal errors=0 rx_no_eop_err=0, rx_no_stp_err=0, rx_no_eop_stp_err=0 rx_no_buf=0, rx_soft_overrun_err=0, dump_err= 0, bogus=0, mxt_flags=0x0 tx_underrun_err=0, tx_soft_underrun_err=0, tx_limited=1(2) tx_fullring=0, tx_started=1, mxt_flush_count=1 rx_int_count=0, tx_int_count=3 M4T: show controller: PAS unit 2, subunit 2, f/w version 1-45, rev ID 0x2800001, version 1 idb = 0x6442F268, ds = 0x64430328, ssb=0x644306E4 Clock mux=0x0, ucmd_ctrl=0x0, port_status=0x7B Serial config=0x8, line config=0x200 maxdgram=1608, bufpool=78Kb, 120 particles DCD=down DSR=down DTR=up RTS=up CTS=down line state: down cable type : V.11 (X.21) DCE cable, received clockrate 2015232 base0 registers=0x3C800000, base1 registers=0x3C802000 mxt_ds=0x644A07A4, rx ring entries=78, tx ring entries=128 rxring=0x7B96D40, rxr shadow=0x64436D40, rx_head=0 txring=0x7B97000, txr shadow=0x6443711C, tx_head=1, tx_tail=1, tx_count=0 throttled=0, enabled=0 halted=0, last halt reason=0 Microcode fatal errors=0 rx_no_eop_err=0, rx_no_stp_err=0, rx_no_eop_stp_err=0 rx_no_buf=0, rx_soft_overrun_err=0, dump_err= 0, bogus=0, mxt_flags=0x0 tx_underrun_err=0, tx_soft_underrun_err=0, tx_limited=1(2) tx_fullring=0, tx_started=1, mxt_flush_count=1 rx_int_count=0, tx_int_count=2 M4T: show controller: PAS unit 3, subunit 3, f/w version 1-45, rev ID 0x2800001, version 1 idb = 0x6443A0A8, ds = 0x6443B168, ssb=0x6443B524 Clock mux=0x0, ucmd_ctrl=0x0, port_status=0x7B Serial config=0x8, line config=0x200 maxdgram=1608, bufpool=78Kb, 120 particles DCD=down DSR=down DTR=up RTS=up CTS=down line state: down cable type : V.11 (X.21) DCE cable, received clockrate 2015232 base0 registers=0x3C800000, base1 registers=0x3C802000 mxt_ds=0x644A07A4, rx ring entries=78, tx ring entries=128 rxring=0x7BA9180, rxr shadow=0x64441B80, rx_head=0 txring=0x7BA9440, txr shadow=0x64441F5C, tx_head=1, tx_tail=1, tx_count=0 throttled=0, enabled=0 halted=0, last halt reason=0 Microcode fatal errors=0 rx_no_eop_err=0, rx_no_stp_err=0, rx_no_eop_stp_err=0 rx_no_buf=0, rx_soft_overrun_err=0, dump_err= 0, bogus=0, mxt_flags=0x0 tx_underrun_err=0, tx_soft_underrun_err=0, tx_limited=1(2) tx_fullring=0, tx_started=1, mxt_flush_count=1 rx_int_count=0, tx_int_count=2