Cisco 3750 Switch connected to a Cisco 1200 AP. Using PoE. Getting Line Protocol down logs in switch. What could be the reason?

[lenins.akm]

The setup is as follows

Cisco 3750 gig port is connected to Cisco 1200 AP Fa port. totally 3 APs are connected. All APs use PoE.

The problem is

I am getting the following logs in switch.  But there is no corresponding logs in AP. I am getting theses logs very frequently for 1 AP and seldom for another AP. no log for third AP.

Jun  2 15:42:42 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to up
Jun  2 15:46:39 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to down
Jun  2 15:46:41 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to up
Jun  2 15:50:46 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to down
Jun  2 15:50:48 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to up
Jun  2 15:54:37 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to down
Jun  2 15:54:39 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to up
Jun  2 16:01:07 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to down
Jun  2 16:01:09 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to up
Jun  2 16:05:13 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to down
Jun  2 16:05:15 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to up
Jun  2 16:14:12 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to down
Jun  2 16:14:14 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to up
Jun  2 16:20:53 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to down
Jun  2 16:20:55 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to up
Jun  2 16:21:01 IST: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/14, changed state to down
Jun  2 16:21:02 IST: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/14, changed state to down
Jun  2 16:21:35 IST: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/14, changed state to up

Please suggest how to solve this.

[glen.grant]

  check cabling for layer 1 issues .   Use the TDR function in the 3750 to check drop to AP .

[lenins.akm]

Thanks a lot for your reply glen

When I run the cable diagnostics, I get the following results,

Interface Speed Local pair Pair length        Remote pair Pair status

--------- ----- ---------- ------------------ ----------- --------------------

Gi1/0/14  100M  Pair A     3    +/- 4  meters Pair A      Normal

                Pair B     3    +/- 4  meters Pair B      Normal

                Pair C     0    +/- 4  meters Pair C      Open

                Pair D     3    +/- 4  meters Pair D      Normal

Does this result indicates any cable issue?