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I having been getting pressure to blog something, so here it is. I received an email from a project manager for some technical help on one of his current projects. I had a project over a year ago where I installed some 7925 wireless phones and integrated with a nurse call system.

When I first read the email, it was like he was speaking a foreign language. The nurse call vendor was asking the engineer on the project for a dial back string. They were asking me if I knew what that was. I was like no, who can remember that shit? So I went to sleep that night and said to myself, “self look at my emails and notes and see if you can’t un-fuck his shit.”

In the morning with a little clearer mind, I started digging through my notes and email. I found something in the first few emails. I started to write up a response but then I realized it was the wrong answer. I finally remembered what I had to do to get it to work. The engineer had configured the FXS ports as MGCP since that was what the sow stated. I said woa, un-fuck that shit, it has to be H.323 since you need dial-peers to insert a pause in the dial string coming from the wireless phone.

You see the nurse call system was interfaced through FXS ports which then went out to the speaker on the hospital bed. The FXS ports were just the method of connecting over to the nurse call system. Once the call rang on the FXS port the nurse call system would answer the call and expect DTMF tones to tell it the room or bed number. So from the wireless phone the nurse would press a button after receiving a text message as an alert from the bed. That would trigger a phone call from the wireless phone to a number string, 1995000303#, for example. In CUCM I created a route pattern of 1995000!# and routed it to the H.323 gateway, stripping the “#”. The gateway then had a dial-peer which would strip 1995000 and “prefix ,,”. See below for example.

!
dial-peer voice 1995000 pots
preference 1
destination-pattern 1995000.T
progress_ind setup enable 3
incoming called-number .
port 0/1/0
prefix ,,
!

So after explaining how digits are stripped by default from destination-patterns unless a no digit strip command is used, I told him to un-fuck his config and make everything h.323 so that he can insert a pause in the middle of a dial string to only forward the room or bed number to the nurse call system.

Sometimes it is good to dust off the old neurons and have to remember shit you don’t use everyday.