On 737 the call should be made at 80 kts ,and the other pilot should check his speed and answer 'checked' . If the speed is not right,he should abort the take off.We had a safety presentation done by a Boeing safety pilot,and it was obvious that it's much safer to abort instead of continuing with unreliable speed (observed by high speed difference at 80 kt call)
The 'hold ' call is not required by Boeing , it must be monitored. The absence of 'hold' is not a reason for RTO , but the pilots must closely monitor the a/t operation during take-off (so it doesn't reduce power due to any fault )
I had some fo's who were doing the 80 kt call :" 80..thrust hold "...so I asked them what if you don't see 'hold' ? you reject? And I've surprised some of them, cause they were doing the check without really thinking of it.
Elroy,on the 737 the autobrake arms at 90 kt.